Directed energy deposition facilitating high speed applications

Abstract

The invention relates to methods, devices and systems for controlling fluid density in the vicinity of a functional object in order to improve one or more related performance metrics. In certain embodiments, the invention relates to forming a low density region near the object by utilizing a directional energy deposition device to deposit energy along one or more paths in the fluid. In certain embodiments, the invention relates to synchronizing energy deposition with one or more parameters that affect the functional performance of the object.

Description

[0001] This application is a divisional of an invention application with an application date of June 20, 2016, priority dates of June 18, 2015 and June 17, 2016, application number 202110534062.0, and name “Directed Energy Deposition for Promoting High-Speed ​​Applications”.

[0002] CROSS REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to: 1) International Application No. PCT / US2016 / 038239, filed on June 17, 2016; 2) U.S. Application No. 15 / 186,337, filed on June 17, 2016; and 3) U.S. Provisional Application No. 62 / 181,625, filed on June 18, 2015. The entire contents of all of the above-mentioned related applications are incorporated herein by reference.

[0004] In addition, the entire contents of the following U.S. patents are each incorporated herein by reference: U.S. Pat. No. 6,527,221 issued on March 4, 2003, U.S. Pat. No. 7,063,288 issued on June 20, 2006, U.S. Pat. No. 7,121,511 issued on October 17, 2006, U.S. Pat. No. 7,648,100 issued on January 19, 2010, U.S. Pat. No. 8,079,544 issued on December 20, 2011, U.S. Pat. No. 8,141,811 issued on March 27, 2012, U.S. Pat. No. 8,511,612 issued on August 20, 2013, U.S. Pat. No. 8,511,612 issued on September 17, 2013 8,534,595, US8,827,211 granted on September 9, 2014, and US8,960,596 granted on February 24, 2015. Field of the Invention

[0005] Energy deposition techniques have been disclosed in the past to achieve significant effects in many applications such as flow control, drag reduction, and vehicle control. When studying the significant effects of depositing energy, many modifications can be made in the manner and / or timing of energy deposition to enhance the benefits of depositing energy when these modifications are not performed. One such modification is to coordinate the energy deposition with one or more other processes so that the effects of the energy deposition are synchronized in "time" or "phase" with such other processes to obtain additional benefits or maximize the relevant effects (the terms "synchronization", "time" and "phase" can be used relatively interchangeably to indicate the timing of an event or process relative to one or more other events and / or processes). Such events and / or processes include, but are not limited to: propulsion processes; fluid dynamic processes; chemical processes; specific movements; injection, addition and / or deposition of additional energy; injection, addition and / or deposition of additional materials; removal of energy; removal of materials; pressure changes; application of one or more forces; combustion processes; ignition processes; detonation processes; and the like. In addition, the concept of energy deposition is broadly interpreted to include any process that adds energy to a medium or causes heating of a medium. This heating or energy deposition can be done quickly enough (e.g., in pulses) to cause the expansion of the medium to be faster than the speed of sound in the medium, thereby causing the area left behind by the expansion to be less dense than the original medium. Another possibility is that the energy deposition and / or the process causing heating can cause a phase change in the medium, which can change the density and / or other properties of the one or more heated media, such as viscosity and / or strength, etc. These changes in one or more media, including density, viscosity and / or strength, etc., can result in changes in the flow properties of the one or more media, as well as changes in other characteristics and responses of the affected media.

[0006] Increase the conveying speed of loom applications such as jets, water jets, shuttle looms, weft looms, etc. by reducing the drag of the shuttle loom. Synchronize the energy deposition to coincide with the conveying of the material woven by the loom. Reduce the drag on the ground vehicle by synchronizing the energy deposition with the movement of the ground vehicle and the instantaneous suspension and propulsion forces, and the energy used to form these forces. Deposit energy in the barrel of a gun, firearm or barrier breaker, and other types of barrels used to propel projectiles, so as to force the air in the barrel to flow out. The reduced drag on the projectile will enable greater muzzle velocities to be achieved with the same drive energy (such as propellant in a conventional gun or electric drive energy in a rail gun). Reduced drag will also allow speeds comparable to those achieved without modification to be achieved by using less drive energy (e.g., a smaller charge, such as less than 90% of the charge, such as between 50% and 90%, less than 70%, or less than 80% of the charge, compared to the standard charge for the particular device). In a conventional gun, this means that the same performance can be achieved with less propellant. The lower propellant requirement then results in reduced muzzle blast when the projectile leaves the barrel. This reduced acoustic signature is useful for minimizing adverse effects on the hearing of nearby individuals, including an operator (or operators). This reduced acoustic signature can also impair detection by acoustic means (similar to acoustic suppressors). The energy deposition that forces air out of the barrel can be applied in a variety of forms. For example, two embodiments can include: i) electromagnetic energy deposition inside the barrel; or ii) the deposition of energy can be chemical in nature; and some combination of these two energy deposition methods. The electromagnetic energy can be, for example, in the form of an electrical discharge inside the barrel. The chemical energy can be, for example, in the form of an additional propellant that, when ignited, expands in front of the projectile to drive the gas from the barrel (as opposed to the traditional role of the propellant expanding behind the projectile to push it out of the barrel). This additional propellant can be incorporated into the body of the round. In powder coating, such as ultrasonic spray deposition applications, the energy deposition is phased by: powder explosion; application of heat; application of electrical discharge; application of laser energy; application of plasma. In ultrasonic and hypersonic propulsion, the energy deposition is phased relative to detonation in an engine (e.g., a pulse detonation engine), which results in proper phasing of the fluid dynamic processes (timing will depend on factors such as the length scale of the vehicle and one (or more) propulsion unit(s), as well as flight conditions and parameters). Propulsion pulses can also be synchronized to generate laser pulses and power to provide pulsed power. Technical Background

[0007] From the beginning, PM&AM Research has pioneered a wide range of energy deposition applications to revolutionize the way the world controls flight and high-speed flows, specifically the way we perform high-speed flight and flow control ranging from high subsonic to hypersonic regimes. There are many applications that give an intuitive sense of the many possibilities opened up by this novel approach. The basic effect stems from our method of rapidly diffusing gas out of the area where we want the high-speed / high-pressure gas to flow through. As a simple analogy (requiring some imagination and permission), consider the difference in effectiveness of the following actions in trying to get a projectile to cross the Red Sea at high speed: either launching that projectile directly from one side of the water to the other, or first "parting" the Red Sea and then launching the same bullet through a path that contains no water ( Figure 1 ).

[0008] In the first case where the bullet is fired directly into high density water, even a large streamlined 1000m / s bullet will penetrate less than 1 meter of water. In the second case, the water is first "parted" (i.e. a path is created that has been cleared of water), after which even the same bullet at 300m / s can be easily transported a long distance (this heuristic embodiment does not address the problem of gravity-induced drop, which is addressed later in this article). We developed this concept and geometry in order to achieve revolutionary control of high-speed flows and high-speed vehicles / projectiles. SUMMARY OF THE INVENTION

[0010] Certain embodiments may provide, for example, a method of propelling an object through a fluid, the method comprising: (i) pulse-heating a portion of the fluid to form a lower density region surrounded by a higher density region, the higher density region containing at least a portion of the heated portion of the fluid; (ii) directing at least a portion of the object into the lower density region; and (iii) detonating a reactant in a pulsed propulsion unit that propels the object. In certain embodiments, for example, steps (i)-(iii) may be repeated, for example, at a rate in the range of 0.1 Hz-100 kHz, such as at a rate in the range of 1 Hz-80 kHz, 10 Hz-50 kHz, 100 Hz-20 kHz, 1-10 kHz, 5-10 kHz, 10-25 kHz, 25-50 kHz; or at a rate in the range of 50-100 kHz.

[0011] In certain embodiments, one or more than one (comprising, such as all) in the following embodiments may include each other embodiment or its part.In certain embodiments, such as, the reactant may be present in the higher density region.In certain embodiments, such as, the heating may include being deposited in the fluid in the range of 1kJ-10MJ, such as in the range of 10kJ-1MJ, 100-750kJ or 200kJ to 500kJ.In certain embodiments, such as, the heating may include in the fluid, by every square meter of cross-sectional area of ​​the object, being deposited in the energy in the range of 10-1000kJ, such as every square meter in the range of 10-50kJ, 50-100kJ, 100-250kJ, 250-500kJ or in the range of 500-1000kJ.In certain embodiments, such as, the heating may include generating shock waves. In some embodiments, for example, the lower density region can have a density in the range of 0.01-10% relative to the density of the ambient fluid, such as a density in the range of 0.5-5%, 1.0-2.5%, or a density in the range of 1.2-1.7% relative to the density of the ambient fluid. In some embodiments, for example, the portion of the fluid can be heated along at least one path. In some embodiments, the at least one path can be formed by energy deposited from a laser, such as a laser filament guided path. In some embodiments, the laser deposition can include laser pulses having a duration in the range of 1 femtosecond to 100 nanoseconds, such as a duration in the range of 10 femtoseconds to 20 picoseconds, 100 femtoseconds to 25 picoseconds, 100 picoseconds to 20 nanoseconds, or a duration in the range of 100 femtoseconds to 30 picoseconds. In some embodiments, the amount of energy deposited by the laser pulse can be in the range of 0.2 mJ to 1 kJ, such as in the range of 1 mJ to 10 mJ, 10 mJ to 3 J, 100 mJ to 10 J, 10 J to 100 J, 100 J to 1000 J, or in the range of 500 mJ to 5 J. In some embodiments, the laser can produce light in the ultraviolet, infrared, or visible portion of the spectrum. In some embodiments, the at least one path can be parallel to the direction of motion of the object. In some embodiments, the lower density region can include a volume in the portion of the heated fluid that extends outward from the at least one path. In some embodiments, for example, the heated portion of the fluid can be heated by an electrical discharge, such as a pulsed electrical discharge. In some embodiments, the electrical discharge can be at a rate of 10 6 -10 7m / s range through the fluid. In some embodiments, the discharge can last for a time in the range of 0.1-100 microseconds, such as a time in the range of 0.1-2 microseconds, 1-5 microseconds, 5-40 microseconds, 10-30 microseconds, or a time in the range of 30-100 microseconds. In some embodiments, the lower density region can be formed within a time in the range of 10-30 microseconds, such as a time in the range of 20-300 microseconds, 20-200 microseconds, 30-100 microseconds, 100-500 microseconds, 400-1500 microseconds, or a time in the range of 500-3000 microseconds. In some embodiments, the lower density region can be destroyed by thermal buoyancy after a period of time in the range of 10-1000 milliseconds, such as a period of time in the range of 20-80 milliseconds, 30-60 milliseconds, 80-120 milliseconds, 150-600 milliseconds, or a period of time in the range of 400-1000 milliseconds. In some embodiments, for example, the object may be in communication with a pulse detonation engine, wherein the pulse detonation engine may contain the reactant. In some embodiments, the detonation may be timed so that the intake nozzle of the pulse detonation engine is present in the higher density region. In some embodiments, the fluid may be air and the pulse detonation engine may be air-breathing. For example, some embodiments may further include: sucking a certain amount of air into the air-breathing pulse detonation engine before step (ii). In some embodiments, the pulse detonation engine may provide at least a portion of the power required to heat the portion of the fluid. In some embodiments, the pulse detonation engine may provide energy to a pulse power supply. In some embodiments, the pulse power supply may provide energy to a filament laser, which forms the path, and the path is capable of guiding a pulse discharge. In some embodiments, the pulse power supply may provide energy to a pulse discharge generator, which is used to heat the portion of the fluid. For example, some embodiments may further include: heating another portion of the fluid to form another lower density region. In some embodiments, the lower density region and the other lower density region may be separated by a region. For example, some embodiments may further include: directing at least another portion of the object into the region. For example, some embodiments may further include: directing at least another portion of the object into another density region. In some embodiments, for example, the heated portion of the fluid may define a tube. In some embodiments, the speed of sound in the tube may be at least 100% greater than the speed of sound in the ambient fluid, such as at least 150%, 200%, 500%, or at least 1000%. In some embodiments, the movement of the object inside the tube may be subsonic. In some embodiments, at least a portion of the movement of the object outside the tube may be ultrasonic.In some embodiments, the tube may have a diameter in the range of 5%-100% of the effective cross-section of the object, such as in the range of 5%-20%, 20%-75%, 30%-50%, 75%-96%, or in the range of 35%-45%. In some embodiments, for example, the object may have a base diameter in the range of 0.5-4m, such as in the range of 1-3m or in the range of 1-2m. In some embodiments, the object may travel in the fluid at a speed in the range of 6-20 Mach, such as in the range of 6-15 Mach, 6-10 Mach, 6-8 Mach, or in the range of 7-8 Mach. In some embodiments, the heating may include depositing energy in the range of 100-750 kJ into the fluid; wherein the object may be characterized by a base diameter in the range of 0.5-4m. In some embodiments, the motion of the object may be hypersonic. In some embodiments, the object may be traveling at a speed in the range of Mach 6-20, such as Mach 6-15, Mach 6-10, Mach 6-8, or Mach 7-8. In some embodiments, the heating may include depositing energy in the range of 100-200 kJ (e.g., in the range of 125-175 or in the range of 140-160 kJ) per square meter of the cross-sectional area of ​​the object into the fluid. In some embodiments, the tube has a cross-sectional area that is 1-25% (e.g., in the range of 2-15%, 3-10%, or 3.5-4.5%) of the cross-sectional area of ​​the object when the object is at an altitude in the range of 10-20 km (e.g., 12.5-17.5 km, 14-16 km, or 14.5-15.5 km). In some embodiments, the tube has a cross-sectional area of ​​6.25-56.25% (e.g., 10-40%, 20-30%, or 24-26%) of the cross-sectional area of ​​the object when the object is at an altitude in the range of 20-40 km (e.g., 25-35 km, 28-32 km, or 29.5-30.5 km). In some embodiments, the tube has a cross-sectional area of ​​25-225% (e.g., 50-200%, 75-150%, or 95-105%) of the cross-sectional area of ​​the object when the object is at an altitude in the range of 40-60 km (e.g., 40-50 km, 42-48 km, or 44-46 km). In some embodiments, in step (ii), the resistance experienced by the object can be reduced by at least 96%. In some embodiments, for example, the object can be in contact with a guide rail. In certain embodiments, for example, the object may be a chamber, a tube, or a barrel.

[0012] Certain embodiments may provide, for example, a vehicle comprising: i) a filamentation laser configured to generate a path in a portion of a fluid surrounding the vehicle; ii) a directed energy deposition device configured to deposit energy along the path to form a low-density region; and iii) a pulse detonation engine. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each of the other embodiments or portions thereof. In certain embodiments, for example, the filamentation laser may include a pulsed laser. In certain embodiments, for example, the directed energy deposition device may include a pulsed discharge generator. For example, certain embodiments may further include: iv) a sensor configured to detect whether a predetermined portion of the vehicle is present in the low-density region; and v) a synchronization controller operably connected to the directed energy deposition device and the pulse detonation engine, the synchronization controller being configured to synchronize the relative timing of the following actions: a) generating a path; and b) depositing energy along the path; and c) operating the pulse detonation engine.

[0013] Certain embodiments may provide, for example, a method of retrofitting a pulsed propulsion vehicle with a directed energy deposition subassembly. The subassembly may be operable to implement and / or include any one or more embodiments described herein.

[0014] Certain embodiments may provide, for example, a method of operating the vehicle, the method comprising: repeating the following steps (i)-(iv) at a rate in the range of 0.1-100 times per second: i) emitting the filamentation laser; simultaneously with ii) discharging the directed energy deposition device; simultaneously with iii) directing at least a portion of the object into the low-density region; and simultaneously with iv) detonating the pulse detonation engine when a predetermined portion of the vehicle enters the low-density region.

[0015] Certain embodiments may provide, for example, a method of reducing base drag generated by a low pressure region near the rear of a vehicle, the method comprising: i) pulsed depositing of energy along at least one path in front of the vehicle, whereby a volume of fluid is displaced from the at least one path; and ii) directing a portion of the displaced volume of fluid into the low pressure region, thereby increasing the pressure of the low pressure region. For example, certain further embodiments may further include: propelling the vehicle by a pulsed propulsion unit, and synchronizing the discharge of the energy deposition device with the generation of propulsion pulses from the pulsed propulsion unit.

[0016] Certain embodiments may provide, for example, a method of reducing wave drag imposed by a fluid against a forward cross-section of a fuselage, the fuselage including a plurality of intake nozzles, the method comprising: i) pulse-heating a portion of the fluid to form a lower density region (e.g., aligned or substantially aligned with a longitudinal center axis of the fuselage) surrounded by the higher density region, the higher density region including at least a portion of the heated fluid; ii) directing a first portion of the fuselage into the lower density region, the first portion of the fuselage not including a plurality of fluid intake nozzles; and simultaneously iii) directing a second portion of the fuselage into the higher density region, the second portion of the fuselage including at least one intake nozzle.

[0017] Certain embodiments may provide, for example, a method for forming a low-density region in a fluid, the low-density region being close to an object, the system comprising: i) using a directed energy dispersion device equipped with a laser assembly to form a plurality of pulsed laser beams emanating from the object and intersecting at one or more coordinates in the fluid, the one or more coordinates being located relative to the object; and ii) depositing energy along one or more paths defined by the plurality of laser beams. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each of the other embodiments or portions thereof. In certain embodiments, for example, depositing energy may include depositing a predetermined amount of energy per unit length of the one or more paths. In certain embodiments, for example, the low-density region may have a characteristic diameter along the one or more paths, wherein the characteristic diameter may be proportional to the square root of the amount of energy deposited per unit length of the one or more paths. In certain embodiments, for example, a tube diameter may be the characteristic diameter. In certain embodiments, for example, the characteristic diameter may further be proportional to the inverse square root of the ambient pressure of the fluid. In certain embodiments, the tube diameter may be the characteristic diameter. In some embodiments, for example, the at least two of the plurality of pulsed laser beams can be formed by separating source laser beams generated by a laser subassembly of the object. In some embodiments, for example, a portion of the fluid can be compressed between the low-density region and the object. In some embodiments, for example, at least a portion of the deposited energy can be delivered by at least one electrode, and at least a portion of the deposited energy can be recovered by at least one other electrode. In some embodiments, for example, a subassembly of the object can include at least one electrode. In some embodiments, for example, a subassembly of the object can include at least one other electrode. In some embodiments, for example, the at least one electrode and / or the at least one other electrode can be positioned in a recessed cavity on the surface of the object.

[0018] Certain embodiments may provide, for example, a method for forming a low-density region in a fluid, the low-density region being proximate to an object, the system comprising: i) directing a laser beam along a line of sight, the laser beam beginning at a coordinate incident upon the object and ending at a coordinate exiting the object; and ii) depositing energy along a path defined by the laser beam.

[0019] Certain embodiments may provide, for example, a method of forming a low-density region in a fluid, the method comprising: i) forming a transfer path configured to direct deposition of energy; and ii) depositing energy along the transfer path to form the low-density region.

[0020] In some embodiments, for example, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or part thereof. In some embodiments, for example, the transmission path may pass through a fluid, such as the atmosphere; and / or along a solid surface, such as along the surface of a vehicle (e.g., an airplane, a missile, a train, a torpedo, and other high-speed vehicles). In some embodiments, for example, the method may further include: repeating steps (i)-(ii) at a rate in the range of 0.1HZ-100kHz, for example, repeating steps (i)-(ii) at a rate in the range of 1Hz-80kHz, 10Hz-50kHz, 100Hz-20kHz, 1-10kHz, 5-10kHz, or repeating steps (i)-(ii) at a rate in the range of 10-30kHz. In some embodiments, for example, forming the transmission path may include emitting one or more energy sources, such as one energy source, two energy sources, three energy sources, or four energy sources. In some embodiments, for example, the one or more energy sources emitted may include electromagnetic radiation, such as x-rays, ultraviolet light, visible light, infrared light, microwaves and / or radio waves; RF plasma discharge; electric current; electron beam; particle beam; charged particle beam; discharge; and / or corona discharge. In some further embodiments, for example, the electromagnetic radiation may be at least one laser beam. In some further embodiments, for example, the first energy source, the second energy source and / or the third energy source may include at least one directed energy beam. In some further embodiments, for example, the electromagnetic radiation may include at least one laser beam. In some further embodiments, for example, the one or more energy sources may include at least one directed energy beam. In some embodiments, for example, forming the transmission path includes emitting a laser beam and an electron beam. In some further embodiments, for example, the laser beam and the electron beam may be emitted simultaneously. In some further embodiments, for example, the laser beam and the electron beam may be emitted sequentially. In some embodiments, for example, emitting the one or more energy sources to form the transmission path may include emitting one or more pulses, a series of pulses, a series of ultrashort pulses, sporadic pulses, random pulses, emission that is close to continuous emission, as continuous energy emission; and / or any or all of these types of emission combinations. In some embodiments, emitting the one or more energy sources to form the transmission path may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 attosecond to 1 femtosecond, such as in the range of 100 femtoseconds to 1 femtosecond.In some embodiments, emitting the one or more energy sources to form the transmission path may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 femtosecond to 100 nanoseconds, such as a duration in the range of 10 femtoseconds to 20 picoseconds, 100 femtoseconds to 25 picoseconds, 100 picoseconds to 20 nanoseconds, or a duration in the range of 100 femtoseconds to 30 picoseconds. In some embodiments, emitting the one or more energy sources to form the transmission path may include at least one pulse, such as a plurality of pulses, having a duration in the range of 100 nanoseconds to 1 microsecond, such as a duration in the range of 500 nanoseconds to 1 microsecond. In some embodiments, emitting the one or more energy sources to form the transmission path may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 microsecond to 10 seconds, such as a duration in the range of 10 microseconds to 1 second, or a duration in the range of 100 microseconds to 500 microseconds. In some embodiments, emitting the one or more energy sources to form the transmission path may include at least one pulse, such as a plurality of pulses, having a duration in the range of 10 seconds to 1 minute, such as a duration in the range of 20 seconds to 40 seconds. In some embodiments, for example, forming the transmission path may include: a) delivering a first energy source to disrupt a property of the fluid (e.g., an area of ​​higher density and / or pressure, such as a wave or wave front); b) introducing a second energy source into the disrupted fluid (e.g., via passing through the entire or interrupted portion of the wave or wave front generated by the first energy source); followed by c) introducing a third energy source into the fluid. In some embodiments, for example, forming the transmission path may include: a) emitting a first energy source to disrupt a standing wave of the fluid near the vehicle; b) passing a second energy source through the disrupted portion of the fluid; followed by c) introducing a third energy source into the fluid to form the transmission path. In some embodiments, for example, the first energy source may include a laser beam; the second energy source may include an electron beam; and the third energy source may include a laser beam. In certain embodiments, for example, the disrupted fluid property can be a wave, such as a standing wave or a dynamic wave, such as a wave adjacent to an object, such as a wave formed by the movement of a vehicle. In certain embodiments, for example, forming the transmission path can include a) introducing a first energy source into the fluid; followed by b) introducing a second energy source into the fluid. In certain further embodiments, for example, the first energy source can be a laser beam or an electron beam, and the second energy source can be a microwave beam. In certain embodiments, for example, forming the transmission path can include forming conductive and / or ionic particles. In certain embodiments, for example, the deposited energy can include the one or more energy sources, such as one energy source, two energy sources, three energy sources, or four energy sources.In certain embodiments, for example, the deposited energy may include one or more forms of energy including electromagnetic radiation, such as x-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves; RF plasma discharges; electric currents; electron beams; particle beams; charged particle beams; discharges; corona discharges; and / or combinations thereof. In certain further embodiments, for example, the electromagnetic radiation may include at least one laser beam. In certain further embodiments, for example, the first energy source, the second energy source, and / or the third energy source may include at least one directed energy beam. In certain further embodiments, for example, the electromagnetic radiation may include at least one laser beam. In certain further embodiments, for example, the one or more energy sources may include at least one directed energy beam. In certain embodiments, for example, the deposited energy may include at least one different form of energy compared to the one or more energy sources used to form the transport path. In certain embodiments, for example, the deposited energy may include at least one common form of energy compared to the one or more energy sources used to form the transport path. In certain embodiments, for example, the deposited energy may be deposited in one or more pulses, a series of pulses, a series of ultrashort pulses, sporadic pulses, random pulses, deposition that is close to continuous deposition, or as a continuous energy deposition. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 nanosecond to 1 femtosecond, such as in the range of 100 nanoseconds to 1 femtosecond. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 femtosecond to 100 nanoseconds, such as in the range of 10 femtoseconds to 20 picoseconds, 100 femtoseconds to 25 picoseconds, 100 picoseconds to 20 nanoseconds, or in the range of 100 femtoseconds to 30 picoseconds. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 100 nanoseconds to 1 microsecond, such as in the range of 500 nanoseconds to 1 microsecond. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 microsecond to 10 seconds, such as in the range of 10 microseconds to 1 second, or in the range of 100 microseconds to 500 microseconds. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 10 seconds to 1 minute, such as a duration in the range of 20 seconds to 40 seconds. In some embodiments, for example, the energy deposition and emission of the one or more energy sources forming the transmission path may occur at different time scales. In some embodiments, for example, the energy deposition and emission of the one or more energy sources forming the transmission path may occur at the same time scale or nearly the same time scale.In certain embodiments, for example, the energy deposition may occur at a faster time scale than the emission of the one or more energy sources forming the transmission path. In certain embodiments, for example, the energy deposition may occur at a slower time scale than the emission of the one or more energy sources forming the transmission path.

[0021] Certain embodiments may provide, for example, a method of propelling a vehicle (e.g., a transport vehicle, a delivery vehicle, a cargo aircraft, an ultrasonic vehicle, a hypersonic vehicle, or a high-altitude vehicle) through an atmosphere, the method comprising: i) heating a portion of the atmosphere in front of and / or beside the vehicle to form a low-density region, comprising: a) forming an initiation region in front of the vehicle, the initiation region being configured to couple and absorb energy deposition; and b) depositing energy in the initiation region to form the low-density region; ii) directing at least a portion of the object into the low-density region; and simultaneously iii) causing a reactant to detonate in a pulsed propulsion unit that propels the vehicle.

[0022] In some embodiments, for example, one or more than one (including, for example, all) of the following embodiments may include each of the other embodiments or portions thereof. In some embodiments, for example, the initiation zone may be in contact with the vehicle. In some embodiments, for example, the initiation zone may not be in contact with the vehicle, for example, the initiation zone may be located in front of the vehicle in the direction of motion. In some embodiments, for example, the initiation zone may be formed up to 4 seconds before the propelled vehicle, for example, up to 3 seconds, 1 second, 500 milliseconds, 10 milliseconds, or 1 millisecond before the vehicle. In some embodiments, for example, the initiation zone may be formed in the range of 1 millisecond to 4 seconds, for example, 10 milliseconds to 3 seconds, 50 milliseconds to 1 second before the propelled vehicle; or may be formed in the range of 100 milliseconds to 500 milliseconds before the propelled vehicle. In some embodiments, for example, the heated portion of the atmosphere may be formed up to 4 seconds before the propelled vehicle, for example, up to 3 seconds, 1 second, 500 milliseconds, 10 milliseconds, or 1 millisecond before the propelled vehicle. In some embodiments, for example, the heated portion of the atmosphere may be formed in the range of 1 millisecond to 4 seconds, such as 10 milliseconds to 3 seconds, 50 milliseconds to 1 second, before the propelled vehicle; or may be formed in the range of 100 milliseconds to 500 milliseconds before the propelled vehicle. In some embodiments, for example, forming the initiation zone may include forming conductive and / or ionic particles. In some embodiments, for example, the method may further include: selecting at least one form of energy for emission to form the initiation zone as a function of the altitude of the vehicle. In some further embodiments, for example, when the vehicle is traveling below a predetermined threshold altitude, the selected at least one form of energy for emission may include a laser beam. In some further embodiments, for example, when the vehicle is traveling at or above a predetermined threshold altitude, the selected at least one form of energy for emission may include an electron beam. In some embodiments, for example, the method may further include: selecting at least one form of energy for deposition in the initiation zone to form the low-density zone. In some further embodiments, for example, when the vehicle is traveling below a predetermined threshold speed, the selected at least one form of energy for deposition may include an electrical discharge. In certain further embodiments, for example, when the vehicle is traveling at or above a predetermined threshold speed, the at least one form of energy selected for deposition may include microwave energy.In some embodiments, for example, the method may further include: repeating steps (i)-(iii) at a rate in the range of 0.1 Hz-100 kHz, for example, repeating steps (i)-(ii) at a rate in the range of 1 Hz-80 kHz, 10 Hz-50 kHz, 100 Hz-20 kHz, 1-10 kHz, 5-10 kHz or repeating steps (i)-(iii) at a rate in the range of 10-30 kHz. In some embodiments, for example, forming the initiation zone may include emitting one or more energy sources, such as one energy source, two energy sources, three energy sources or four energy sources. In some embodiments, for example, the one or more emitted energy sources may be selected from the following: electromagnetic radiation, such as x-rays, ultraviolet rays, visible light, infrared rays, microwaves and radio waves; RF plasma discharge; electric current; electron beam; particle beam; charged particle beam; discharge; and corona discharge. In some further embodiments, for example, the electromagnetic radiation may be at least one laser beam. In some further embodiments, for example, the first energy source, the second energy source and / or the third energy source may include at least one directed energy beam. In certain further embodiments, for example, the electromagnetic radiation may include at least one laser beam. In certain further embodiments, for example, the one or more energy sources may include at least one directed energy beam. In certain embodiments, for example, forming the initiation zone includes emitting a laser beam and an electron beam. In certain further embodiments, for example, the laser beam and the electron beam may be emitted simultaneously. In certain further embodiments, for example, the laser beam and the electron beam may be emitted sequentially. In certain embodiments, for example, emitting the one or more energy sources to form the initiation zone may include emitting one or more pulses, a series of pulses, a series of ultrashort pulses, sporadic pulses, random pulses, emission that is close to continuous emission, as continuous energy emission. In certain embodiments, emitting the one or more energy sources to form the initiation zone may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 attosecond to 1 femtosecond, such as in the range of 100 femtoseconds to 1 femtosecond. In some embodiments, emitting the one or more energy sources to form the initiation zone may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 femtosecond to 100 nanoseconds, such as a duration in the range of 10 femtoseconds to 20 picoseconds, 100 femtoseconds to 25 picoseconds, 100 picoseconds to 20 nanoseconds, or a duration in the range of 100 femtoseconds to 30 picoseconds. In some embodiments, emitting the one or more energy sources to form the initiation zone may include at least one pulse, such as a plurality of pulses, having a duration in the range of 100 nanoseconds to 1 microsecond, such as a duration in the range of 500 nanoseconds to 1 microsecond.In some embodiments, emitting the one or more energy sources to form the initiation zone may include at least one pulse, such as multiple pulses, with a duration in the range of 1 microsecond to 10 seconds, such as a time in the range of 10 microseconds to 1 second or a time in the range of 100 microseconds to 500 microseconds. In some embodiments, emitting the one or more energy sources to form the initiation zone may include at least one pulse, such as multiple pulses, with a duration in the range of 10 seconds to 1 minute, such as a time in the range of 20 seconds to 40 seconds. In some embodiments, for example, the deposited energy may include one or more energy sources, such as one energy source, two energy sources, three energy sources, or four energy sources. In some embodiments, for example, the deposited energy may include one or more forms of energy selected from the following: electromagnetic radiation, such as x-rays, ultraviolet rays, visible light, infrared rays, microwaves, and radio waves; RF plasma discharge; electric current; electron beam; particle beam; charged particle beam; discharge; and corona discharge. In some further embodiments, for example, the electromagnetic radiation may be at least one laser beam. In some further embodiments, for example, the first energy source, the second energy source, and / or the third energy source may include at least one directed energy beam. In certain further embodiments, for example, the electromagnetic radiation may include at least one laser beam. In certain further embodiments, for example, the one or more energy sources may include at least one directed energy beam. In certain embodiments, for example, the deposited energy may include at least one different form of energy compared to the one or more energy sources used to form the initiation zone. In certain embodiments, for example, the deposited energy may include at least one common form of energy compared to the one or more energy sources used to form the initiation zone. In certain embodiments, for example, the deposited energy may be deposited in one or more pulses, a series of pulses, a series of ultrashort pulses, sporadic pulses, random pulses, a deposition that is close to continuous deposition, or as a continuous energy deposition. In certain embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 nanosecond to 1 femtosecond, such as in the range of 100 nanoseconds to 1 femtosecond. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 femtosecond and 100 nanoseconds, such as a duration in the range of 10 femtoseconds to 20 picoseconds, 100 femtoseconds to 25 picoseconds, 100 picoseconds to 20 nanoseconds, or a duration in the range of 100 femtoseconds to 30 picoseconds. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 100 nanoseconds to 1 microsecond, such as a duration in the range of 500 nanoseconds to 1 microsecond.In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 1 microsecond to 10 seconds, such as a duration in the range of 10 microseconds to 1 second, or a time in the range of 100 microseconds to 500 microseconds. In some embodiments, the energy deposition may include at least one pulse, such as a plurality of pulses, having a duration in the range of 10 seconds to 1 minute, such as a time in the range of 20 seconds to 40 seconds. In some embodiments, for example, the energy deposition and the emission of the one or more energy sources forming the initiation zone may occur at different time scales. In some embodiments, for example, the energy deposition and the emission of the one or more energy sources forming the initiation zone may occur at the same time scale or nearly the same time scale. In some embodiments, for example, the energy deposition may occur at a faster time scale than the emission of the one or more energy sources forming the initiation zone. In some embodiments, for example, the energy deposition may occur at a slower time scale than the emission of the one or more energy sources forming the initiation zone.

[0023] In certain embodiments, for example, a particular laser assembly may not be effective or may have reduced efficiency for forming a path for energy deposition in the fluid, for example, when the fluid has a pressure and / or density less than a threshold value and / or when the vehicle is operating above a threshold speed and / or altitude. In certain further embodiments, for example, when a particular laser configuration is not fully effective, a particle beam, such as an electron beam, may be employed, alone or in combination with another energy source (e.g., a laser beam), to form a path for energy deposition. In certain embodiments, an apparatus, such as a vehicle, may include a sensor for detecting reduced effectiveness, and the apparatus may further include a controller configured to switch from using the laser configuration to using an electron beam (or energy source) to increase the effectiveness of path formation.

[0024] Certain embodiments may provide, for example, a method of propelling a ground vehicle (e.g., a train, a maglev, a high-speed train, a bullet train, and a hyperloop) coupled to a track assembly, the method comprising: i) accumulating electrical energy storage on the ground vehicle; ii) pulsed release of at least a portion of the electrical energy from the ground vehicle to a conductive portion of the track assembly, the portion being located forward of the body of the ground vehicle, whereby a portion of air proximate to the released electrical energy expands to form a lower density region surrounded by a higher density region; iii) directing at least a portion of the object into the lower density region; concurrently with iv) detonating a reactant in a pulsed propulsion unit that propels the object. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each of the other embodiments or portions thereof. In certain embodiments, for example, the electrical energy storage may be pulsed to the ground vehicle from one or more booster subassemblies of the track assembly. In certain embodiments, for example, the ground vehicle may be maglev.

[0025] Some embodiments may provide, for example, a ground vehicle transportation system (e.g., a train, maglev, high-speed train, bullet train, and hyperloop), the system comprising: i) a track assembly comprising: a) a track; b) a power source; ii) a storage device, such as a capacitor, configured to receive and store a portion of the power source; iii) a laser configured to generate at least one path connecting one or more electrodes present on the body of the ground vehicle with a portion of the track assembly, the portion of the track assembly being located in front of the vehicle; iv) a directed energy deposition device configured to deposit a portion of the stored power source along the at least one path; and v) a controller configured to synchronize the receipt of the portion of the power source, the generation of the at least one path, and the deposition of the portion of the stored power source.

[0026] Certain embodiments may provide, for example, a method of modifying a ground vehicle (e.g., a train, a maglev, a high-speed train, a bullet train, a hyperloop, a high-speed passenger vehicle, and an automobile) to reduce drag, the method comprising: installing a directed energy deposition subassembly configured to receive energy from a power source of the ground vehicle and deposit the energy on a path connecting a fuselage of the vehicle with a ground coordinate located in front of the fuselage.

[0027] Certain embodiments may provide, for example, a method of propelling an object in a barrel containing a fluid (e.g., a barrel associated with a firearm, and a railgun), the method comprising: i) heating at least a portion of the fluid; ii) causing at least a portion of the fluid to be expelled from the barrel to form a low-density region in the barrel; followed by iii) igniting and / or detonating a reactant adjacent to the object.

[0028] In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or part thereof. In certain embodiments, for example, the reactant may be an explosive and / or a propellant (e.g., a chemical propellant). In certain embodiments, for example, the reactant may be attached to the object. In certain embodiments, for example, the fluid may be air. In certain embodiments, for example, at least a portion of the fluid may be heated by discharge, for example, by an arc between two electrodes (e.g., insulated electrodes) located in a hole of the barrel, along the hole, or near the hole. In certain embodiments, for example, at least a portion of the fluid may be heated by igniting a chemical reactant. In certain embodiments, the chemical reactant may be attached to the object or positioned therewith. In certain embodiments, the chemical reactant may be ignited by an electric pulse. In certain embodiments, the electric pulse may be provided by the object. In certain embodiments, the electric pulse may be provided by a piezoelectric generator. In certain embodiments, for example, the fluid may be a gas. In certain embodiments, for example, the fluid may be air. In certain embodiments, the fluid may be a liquid. In certain embodiments, the fluid may be compressible. In some embodiments, the fluid can be incompressible. In some embodiments, the heated portion of the fluid can be heated to undergo a phase change. In some embodiments, for example, the portion of the fluid can be heated by igniting and / or detonating a chemical reactant, for example, by an electric pulse. In some embodiments, the electric pulse can be provided by the object, for example, by a mechanism partially or completely contained in the object. In some embodiments, the electric pulse can be provided by a piezoelectric generator, for example, a piezoelectric generator partially or completely contained in the object. In some embodiments, for example, the object is a projectile, such as a bullet. In some embodiments, for example, the barrel can be a part of a firearm or a part of a rail gun. In some embodiments, for example, the heating can reduce the viscosity of the heated portion of the fluid. In some embodiments, for example, at least a portion of the fluid can be heated by a discharge in an energy range of 5-120J, for example, in an energy range of 10-100J, 10-30J, 25-75J or in an energy range of 25-50J. In some embodiments, for example, the method can further include expelling the object from the barrel. In some embodiments, the object can be a projectile. In some embodiments, the barrel can be a component, such as a component of a railgun. In some embodiments, for example, the magnitude of the generated acoustic signature can be at least 10% less than the magnitude of the acoustic signature of a conventional .30-06 rifle, a conventional 300 horsepower rifle, a jet engine at takeoff, and / or an M2 howitzer, such as 10% to 50%, at least 25%, 50%, or at least 75% less.In some embodiments, for example, the magnitude of the generated acoustic wave signature can be less than 300 dB, such as between 50 dB and 150 dB, less than 250 dB, 200 dB, 175 dB, 150 dB, or less than 125 dB.

[0029] Certain embodiments may provide, for example, a method for delivering a projectile, the method comprising: i) a barrel including a breech configured to operably receive the projectile into a bore of the barrel; ii) a barrel cleaning system comprising: a pulse heating system located within and / or adjacent the bore, the pulse heating system configured to expel a portion of a fluid present in the bore; and) a projectile launching system.

[0030] In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each of the other embodiments or portions thereof. In certain embodiments, for example, the pulsed heating system may be proximate to the breech. In certain embodiments, for example, the pulsed heating system may further include a chemical propellant. In certain embodiments, the chemical propellant may be integral to the projectile and / or the box containing the projectile. In certain embodiments, for example, the pulsed heating system may further include a pulsed discharge generator that may be configured to deposit energy along at least one path in the bore. In certain embodiments, the pulsed heating system may further include a pulsed filamentation laser that may be configured to generate the at least one path. In certain embodiments, the pulsed filamentation laser may be powered by a chemical propellant that is proximate to the projectile and / or integral to the box containing the projectile. In certain embodiments, the pulsed filamentation laser may be integral to the projectile and / or the box containing the projectile.

[0031] For example, certain embodiments may further include a synchronization controller that may be configured to control the relative timing of operation of the barrel cleaning system and operation of the projectile launching system.

[0032] Certain embodiments may provide, for example, a method of retrofitting a projectile delivery system, the method comprising installing a directed energy deposition subassembly configured to deposit energy into a bore of a barrel of the projectile delivery system.

[0033] Certain embodiments may provide, for example, a method of propelling a projectile through a bore of a barrel equipped with the barrel cleaning system, the method comprising: i) operating the barrel cleaning system to expel a portion of the fluid from the bore; followed a few milliseconds later by ii) priming a projectile launching system.

[0034] Certain embodiments may provide, for example, a method of reducing the acoustic signature of a projectile by providing the barrel with a cleaning system.

[0035] Certain embodiments may provide, for example, a gun configured to breach a barrier (such as a door) (sometimes referred to as a barrier breaching gun), the gun comprising: i) a ported barrel, the barrel including a breech that is operable to receive a shotgun cartridge inserted into a bore of the barrel; ii) a barrel cleaning system, the barrel cleaning system comprising: a pulse heating system located within the bore, the pulse heating system configured to expel at least a portion of the fluid present in the bore; and iii) a firing system.

[0036] Certain embodiments may provide, for example, a firearm barrel configured for use in an obstacle breaching gun, comprising: i) a propellant proximate the rear of the barrel, the propellant also proximate at least one projectile; ii) a directed energy deposition device, such as a prepropellant, proximate the at least one projectile opposite the propellant, the directed energy deposition device being configured to discharge at least 98% of the gas initially at atmospheric conditions from the barrel of the gun after igniting the prepropellant; and iii) a launch system coupler configured to synchronize the operation of the directed energy deposition device prior to detonation of the propellant. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each of the other embodiments or portions thereof. In certain embodiments, for example, the launch system coupler may further include a prepropellant booster charge operably connected to the launch system of the gun.

[0037] Certain embodiments may provide, for example, a method of altering a shock wave approaching the chassis of a vehicle (e.g., a military vehicle, an armored vehicle, a Humvee, an armored personnel carrier, a passenger car, a train, and / or a minesweeper), the vehicle being in contact with an underlying surface and being present in a fluid, the method comprising: i) heating a portion of the fluid along at least one path to form at least one volume of heated fluid extending outward from the path, the path extending between the chassis and the underlying surface; and ii) timing the heating to alter the shock wave.

[0038] In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each of the other embodiments or portions thereof. In certain embodiments, for example, the total momentum imparted to the vehicle by the shock wave may be reduced by at least 10%, for example, by at least 20%, 30%, 40%, or at least 50%. In certain embodiments, for example, the average acceleration experienced by the vehicle due to the shock wave may be reduced by at least 40%, for example, by at least 50%, 60%, 70%, or at least 80%. In certain embodiments, for example, the portion of the fluid may be heated by discharge. In certain embodiments, for example, the portion of the fluid may be heated by depositing at least 3 PV units of energy, where P is the ambient pressure of the fluid and V is the volume of the fluid present between the chassis and the lower surface.

[0039] Certain embodiments may provide, for example, a method of altering a blast wave approaching a surface, the method comprising: i) heating a portion of the surface to form at least one hole in the surface; and ii) timing the heating to form the at least one hole before the blast wave leaves the surface.

[0040] In some embodiments, one or more than one (including, for example, all) of the following embodiments may include each of the other embodiments or portions thereof. In some embodiments, for example, the portion of the surface may be heated by depositing energy onto the surface. In some embodiments, for example, the amount of energy deposited onto the surface may be in the range of 1 kJ-10 MJ, for example, in the range of 10 kJ-1 MJ, 100-750 kJ, or in the range of 200 kJ to 500 kJ. In some embodiments, for example, the surface may be a road surface, soil, and / or covering beneath the chassis of a vehicle. In some embodiments, the portion of the surface may be heated by depositing on the surface an amount of energy in the range of 200-500 kJ, for example, in the range of 250-400 kJ or 300-350 kJ per cubic meter of volume present between the chassis and the surface. In some embodiments, the blast wave may have an energy in the range of 100-500 MJ, for example, an energy in the range of 200-400 MJ. In certain embodiments, the amount of energy deposited can reduce the energy transferred from the blast wave to the vehicle to at least 1 / 10, such as at least 1 / 20, 1 / 50, 1 / 100, or at least 1 / 200, the amount of energy deposited. In certain embodiments, the net acceleration transferred to the vehicle due to the blast wave can be reduced by at least 10%, such as at least 20%, 30%, 40%, or at least 50%. In certain embodiments, the portion of the surface can be heated by electron emission from the vehicle.

[0041] Certain embodiments may provide, for example, a method of mitigating explosion gases near the base of a vehicle (e.g., a military vehicle, an armored vehicle, a Humvee, an armored personnel carrier, a passenger vehicle, a train, and / or a minesweeper) that is present in a fluid, the method comprising: i) heating a portion of the fluid along at least one path extending from the chassis to an exterior of the vehicle to form at least one low-density channel; and ii) timing the heating so that the at least one low-density channel receives at least a portion of the explosion gases.

[0042] Certain embodiments may provide, for example, a vehicle equipped with an explosion mitigation device, the explosion mitigation device comprising: i) a sensor configured to detect an initial blast wave beneath a chassis of the vehicle; ii) a directed energy deposition device configured to deposit energy along at least one path, the at least one path being located beneath the chassis of the vehicle; and iii) a synchronization controller configured to time the operation of the directed energy deposition device relative to the detection of the initial blast wave. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each of the other embodiments or portions thereof. In certain embodiments, for example, the energy deposition may be configured to heat a portion of the fluid along at least one path to form at least one volume of heated fluid extending outward from the path. In certain embodiments, for example, the energy deposition may be configured to form at least one hole in a surface located beneath the chassis of the vehicle.

[0043] Certain embodiments may provide, for example, a vehicle (e.g., a military vehicle, an armored vehicle, a Humvee, an armored personnel carrier, a passenger vehicle, a train, and / or a minesweeper) equipped with a blast mitigation device, the blast mitigation device comprising: i) a sensor configured to detect an initial blast wave beneath a chassis of the vehicle; ii) a directed energy deposition device configured to deposit energy along at least one path extending from the chassis of the vehicle to an exterior of the vehicle; and iii) a synchronization controller configured to time the operation of the directed energy deposition device relative to the detection of the initial blast wave.

[0044] Certain embodiments may provide, for example, a method of mitigating an explosion from an improvised explosive device using a vehicle (e.g., a military vehicle, an armored vehicle, a Humvee, an armored personnel carrier, a passenger vehicle, a train, and / or a minesweeper) equipped with an explosion mitigation device. In certain embodiments, for example, the improvised explosive device may be buried.

[0045] Certain embodiments may provide, for example, a method of modifying a vehicle to withstand an explosion, the method comprising: installing a directed energy deposition subassembly configured to deposit energy beneath the chassis of the vehicle.

[0046] Certain embodiments may provide, for example, a method of ultrasonically depositing a spray onto a surface, the method comprising: i) directing at least one laser pulse through a fluid onto the surface to form at least one path through the fluid, the at least one path being located between an ultrasonic nozzle and the surface; ii) releasing a certain amount of electrical energy along the path to form a low-density tube; a few microseconds later, followed by iii) discharging powder, particles and / or atomized material from the ultrasonic nozzle into the low-density tube. In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or a portion thereof. In certain embodiments, for example, steps (i)-(iii) may be repeated at a rate in the range of 0.1 Hz-100 kHz, for example, at a rate in the range of 1 Hz-80 kHz, 10 Hz-50 kHz, 100 Hz-20 kHz, 1-10 kHz, 5-10 kHz, or at a rate in the range of 10-30 kHz.

[0047] Certain embodiments may provide, for example, a spray deposition apparatus comprising: i) a nozzle configured to spray particles and / or atomized material onto a surface; ii) a pulsed filamentation laser configured to generate at least one path between the nozzle and the surface; iii) a pulsed discharge generator configured to deposit energy along the at least one path to form a low-density tube; and iv) a synchronization controller configured to synchronize the generation of the at least one path, the deposition of energy, and the relative timing of the spray. In certain embodiments, one or more of the following embodiments (including, for example, all) may include each other embodiment or a portion thereof. In certain embodiments, for example, the spray may be an ultrasonic spray.

[0048] Certain embodiments may provide, for example, a method of performing physical vapor deposition using the spray deposition apparatus. For example, certain embodiments may include depositing a metal powder onto a metal surface.

[0049] Certain embodiments may provide, for example, a method of sandblasting using the spray deposition apparatus.

[0050] Certain embodiments may provide, for example, a method of retrofitting an ultrasonic spray device, the method comprising: installing a directed energy deposition subassembly configured to deposit energy in a path connecting a nozzle of the spray device and a surface.

[0051] Certain embodiments may provide, for example, a method of operating an intermittent weaving machine or loom (e.g., an air jet weaving machine, a water jet weaving machine, a shuttle weaving machine, a weft loom, and / or a high-speed weaving machine) to form a fabric, wherein the air jet weaving machine is configured to receive a weft yarn and is further configured to form a warp span, the method comprising: depositing energy to form a low-density guide path for the weft yarn through the span.

[0052] In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or part thereof. In certain embodiments, for example, the deposited energy may include energy deposited in the range of 5-50 mJ (e.g., in the range of 5-8 mJ, 8-10 mJ, 10-15 mJ, 15-20 mJ, 20-30 mJ, 30-40 mJ, or in the range of 40-50 mJ per 1 mm diameter weft yarn per 10 cm guide path; or at least 8 mJ, at least 20 mJ, or at least 40 mJ). In certain embodiments, for example, the weft yarn may have a diameter in the range of 0.1-1 mm, such as a diameter in the range of 0.25-0.75 mm, or a diameter in the range of 0.5-0.7 mm, such as a diameter of 0.6 mm. In some embodiments, for example, the weft yarn can travel through the guide path at a speed in the range of 100-500 m / s, such as a speed in the range of 200-400 m / s; or at a speed of at least 200 m / s, such as at least 250 m / s, 300 m / s; or at least 350 m / s. In some embodiments, for example, the weft yarn can travel through the guide path at a speed in the range of greater than 0.1 Mach, such as at a speed greater than 0.3 Mach, 0.8 Mach, 1 Mach, or at a speed greater than 1.5 Mach. In some embodiments, for example, the fabric can be formed at a speed in the range of 500-60,000 weft yarns per minute, such as 2000-50,000 weft yarns per minute, 8,000-30,000 weft yarns per minute; or at a speed in the range of 15,000-25,000 weft yarns per minute. In certain embodiments, for example, the guide path may be cylindrical.

[0053] For example, some embodiments may further include: advancing the weft yarn into the low-density guide path with a burst of high-pressure air. In some embodiments, the burst of high-pressure air may be synchronized with the energy deposition. In some embodiments, the low-density guide path may be formed downstream of the burst of high-pressure air.

[0054] In some embodiments, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or a portion thereof. In some embodiments, for example, another portion of the energy may be deposited downstream of the supercharger air source to form another low-density guide path. In some embodiments, for example, the weft yarn may be wetted with a certain amount of water. In some embodiments, at least a portion of the amount of water may evaporate in the low-density guide path.

[0055] Certain embodiments may provide, for example, a weaving machine (e.g., an air jet weaving machine, an intermittent air jet weaving machine, a water jet weaving machine, a shuttle weaving machine, a weft weaving machine and / or a high-speed weaving machine), the air jet weaving machine being configured to form a fabric, the weaving machine comprising: i) a device comprising a plurality of profiled reeds mounted on a sley, the device being configured to form a warp shed; ii) a directed energy deposition assembly, the assembly being configured to generate a low-density guide path through the warp shed; and iii) a weft nozzle connected to a pressurized air source, the weft nozzle being configured to push a portion of the weft yarn through the low-density guide path. In certain embodiments, one or more than one (including, for example, all) of the following embodiments may include each other embodiment or a portion thereof. In certain embodiments, for example, the length of the warp shed may be in the range of 3-30 m, for example, in the range of 4-4.5 m, 4.5-6 m, 6-8 m, 8-10 m, 5 -25 m or in the range of 10-20 m.

[0056] Certain embodiments may provide, for example, a method of retrofitting a weaving machine (e.g., an air jet weaving machine, a water jet weaving machine, a shuttle weaving machine, a weft weaving machine, and / or a high-speed weaving machine), the method comprising: installing a directed energy deposition subassembly configured to deposit energy on a path connecting a yarn distribution nozzle of the weaving machine with electrodes located on opposite sides of the weaving machine and passing through the contours of multiple reeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A and Figure 1 B. Schematic diagram comparing (1A) the ineffective case of a bullet trying to propagate through water at high speed, with (1B) the effortless case of the same bullet propagating after the water is moved laterally out of its path. In the brute force approach, the energy of the bullet is quickly transferred to the water (and material deformation). In our approach, the bullet travels a longer distance, interacting with its surroundings through weaker forces.

[0058] Figure 2 A and 2B. Strong discharges can be used to deposit energy along arbitrary geometries on a surface, the examples described here being (2A) a semicircular path and (2B) a straight line.

[0059] Figure 3 .Time series of schlieren images showing the energy deposition along a resulting blast wave (supersonic shock wave) that pushes away a region of hot, low-density gas ( Figure 3 left and middle images), where the shock wave propagates at the speed of sound after its intensity decreases to Mach 1 ( Figure 3 middle right image), and can no longer drive / push away this low density area.

[0060] Figure 4 : Intense laser pulses are focused onto a point in the air to deposit energy in the air with an intensity sufficient to effectively ionize the gas molecules instantaneously compared to the fluid response.

[0061] Figure 5 .Shadow image display from Figure 4 The laser "spark" shown drives a blast wave that opens a region of low-density gas that persists for a long time as a low-density region in the ambient gas.

[0062] Figure 6 The laser filament creates a straight ionization channel along the path of the ultrashort laser pulse.

[0063] Fig. 7A and 7B .Laser filaments from ultrashort laser pulses can be used to precisely trigger and discharge along their (7B) straight path, which is typically less controlled in space and time than (7A).

[0064] Figure 8 .Very small low density "tubes" are depicted here in place of the larger tubes.

[0065] Fig. 9A and 9B (9A) Combined force and (9B) impulse applied by an explosion beneath a test panel as a function of time, with different initial densities beneath the vehicle (100%, 10%, and 7.5% of ambient density).

[0066] Fig.10 .Conceptual illustration of a conductive path along the surface of a vehicle to quickly direct high pressure gas out of the confined space beneath a land vehicle.

[0067] Fig.11 As the cone travels through the low density tube that deposits energy upstream along the cone's stagnation line, the drag on the cone decreases significantly. The letters on the graph correspond to the times marked by the vertical lines next to the letters, which correspond to Fig.14 The frames in are similarly labeled.

[0068] Fig.12 .for Fig.13The parameters that were varied for the research results shown in include: four Mach numbers → M = 2, 4, 6, 8; three cone half angles → 15°, 30°, 45°; and four low-density "tube" diameters → 25%, 50%, 75% and 100% of the base diameter of the cone.

[0069] Fig.13 Drag reduction and return on energy invested are plotted for 15 / 30 / 45 degree cones propagating at Mach 2, 4, 6, 8 through tubes with diameters of 25%, 50%, 75% and 100% of the base diameter of the cone. In some cases, almost all drag is removed, and in all cases the energy required to open the "tube" is less than the energy saved in drag reduction, showing a return of up to 65 times the energy deposited in front of the cone).

[0070] Fig.14 A-14D. In the corresponding Fig.11 Density profiles taken at the times marked in , show the flow changes as the cone flies through the low density "tube". The sequence from 14A to 14D shows a large reduction in the bow shock (with its wave drag and sonic boom), and a strong repressurization of the base, indicating the removal of base drag and increased propulsive effect of the exhaust products at the base.

[0071] Fig.15 .The conductive paths 108 can be sprayed and directed into the air to allow for the discharge required to control / modify the shockwave of the vehicle.

[0072] Fig.16 . Schematic diagram of a laser pulse split by multiple electrically isolated focusing / discharging devices.

[0073] Fig.17 . A schematic diagram of the optical path / elements for focusing the laser pulse through the conical housing electrode (123) is shown.

[0074] Fig.18 . Schematic example of how an array of discharge devices can be used to enhance the energy deposition and create a larger core by phasing multiple smaller discharges.

[0075] Fig.19 .Illustrative example of how an array of discharge devices can be used to increase the energy deposition and "purge" the flow in a desired direction by phasing of multiple smaller discharges.

[0076] Fig. 20A and 20B. In the three-dimensional run, the initial core position is axisymmetric with the vehicle (20a), achieving maximum drag reduction and no lateral forces or torques. The core then gradually moves upward as the run progresses, allowing quasi-steady-state values ​​of control forces and torques to be monitored over the entire range of core positions. We characterize this as an offset of approximately 1 / 2 of the base radius (20b).

[0077] Fig.21 .Framework for a test run using a standard cone to study the effects on heating, drag and control forces when creating a hot low-density core in the shock wave front of a hypersonic vehicle. Fig.21 Top - density; bottom left - pressure; bottom right - temperature; bottom right - drag, force and torque. )

[0078] Fig. 22 .Low density tubes can also be created from the side of the vehicle with an oblique shock wave to facilitate imaging and release of the secondary vehicle without slowing the primary vehicle.

[0079] Fig.23 AF. Top row (left to right, 23A-C) - shock waves open up low-density "hemispheres" on surfaces in still air, caused by energy pulse-deposited at a distance using laser pulses. Bottom row (left to right, 23D-F) - the same laser pulses are used to pulse-deposit energy and create shock waves that open up similar low-density "hemispheres" transported by convection of air shown flowing along the same surface.

[0080] Fig.24 AD. Plots of relative pressure as a function of the dimensionless radius of a cylindrical impact at different dimensionless times. The initial (undisturbed) gas pressure is p o .

[0081] Fig.25 AD. Plot of the flow Mach number as a function of the dimensionless radius of a cylindrical shock at different dimensionless times. The speed of sound before the shock is a o .

[0082] Fig.26 AD. Plot of relative density as a function of the dimensionless radius of a cylindrical impact at different dimensionless times. The initial (undisturbed) gas density is ρ o .

[0083] Fig. 27 .Time sequence of Nd:YAG laser discharge at 3.45 Mach flow rate ( Fig. 27(left to right) Schlieren images. The laser incidence is from bottom to top and because the CCD pixels are saturated, the light spot remains visible. The free-flow flow direction is from right to left.

[0084] Fig.28 Time-lapse schlieren image of a heated spot as it flows leftward in an ultrasonic wind tunnel to interact with the normal bow wave of a spherical model. The measured pressure baseline and instantaneous data along the sphere are also depicted in this figure as lines around the sphere.

[0085] Fig.29 The time history of the pressure at the stagnation points of the model at three energy levels

[0086] Fig.30 Simulation results of filament diameter and electron concentration as a function of propagation distance for an initial power of 49.5 MW. Significant photoionization is only seen to occur over short lengths where beam confinement is greatest.

[0087] Fig.31 Simulation results of the filament envelope diameter as a function of propagation distance for an initial power of 160 MW. The filament diameter remains roughly constrained to within 100 microns over thousands of kilometers.

[0088] Fig.32 .Laser initiated / guided discharge within 30cm. Ionizing UV laser pulses are sent through the hole in the lower electrode and through the hole in the upper electrode.

[0089] Fig.33A -D. Fig.33A It is a single laser ionization path; Fig.33B is the discharge that follows the path created by this laser ionization path; Fig.33C are two ionization paths generated by two separate laser pulses; Fig.33D It is a discharge that follows the V-shaped path created by the two laser pulses.

[0090] Fig.34A and 34B . Fig.34A It is an aviation window designed under the guidance of Dr. Wilhelm Behrens of TRW. Fig.34B It is a complete setup with high pressure inlet, aviation windows, vacuum tubes and exhaust lines.

[0091] Fig.35 .Schematic diagram of the pulse detonation engine cycle.

[0092] Fig.36 AH. Second conceptual diagram of the dynamics in a pulse detonation engine.

[0093] Fig.37. Schematic diagram of an embodiment of an air jet braiding machine with an integrated directed energy deposition device.

[0094] Fig.38 . Schematic diagram of an embodiment of a firearm subassembly having an integral directed energy deposition device.

[0095] Fig.39 .A schematic diagram depicting a conceptual example of an ultrasonic impinging jet flow field that may occur in a continuous ultrasonic multiphase flow application such as spraying or powder coating.

[0096] Fig.40 . Schematic diagram depicting a conceptual example of a cold gas dynamic spray system.

[0097] Fig.41 . Schematic diagram of an embodiment of a vehicle equipped with a explosion mitigation device.

[0098] Fig.42 . Schematic diagram of an embodiment of a vehicle equipped with a terrain changing device.

[0099] Fig.43 . Schematic diagram of an embodiment of a directed energy deposition apparatus having a pulsed laser subassembly.

[0100] Fig.44 . Schematic diagram of an embodiment of a firearm barrel having an integral directed energy deposition device. DETAILED DESCRIPTION OF THE INVENTION

[0102] The basic idea behind the energy deposition method of the present invention is that we are able to redistribute / shape the density of air by rapidly ("pulsed") depositing energy into the air. It is important to note that in order to effectively "break apart" the air, the deposition of this energy (e.g., in the form of short laser or microwave pulses; and / or techniques such as electrical discharges) must be much faster than the gas can expand. Any heating that allows the gas to spread out as it is heated, even if very high temperatures are used, will not achieve the efficient results we describe here. Generally speaking, "sudden" / "pulsed" heating processes will produce a "pop" or "pop" sound.

[0103] In order to: i) adjust the intensity and spatial distribution of specific energy deposition patterns; ii) maintain specific paths and channels for proper transmission; and iii) achieve coupling of energy into the flow; various energy deposition techniques can be applied to address a variety of possible atmospheric and flow conditions in the widest range of applications. The most effective energy deposition method: forming a nucleation / guiding / initiating area (e.g., an initial path) into which more energy is deposited; or depositing more energy into such an initial area or path; will depend on the atmospheric conditions in which they are to be formed / through (including all represented media and mixed phases, such as gas, liquid, solid, plasma), and the relevant operating flow conditions. Certain atmospheric and flow conditions may require the formation of an initial path via deposition of energy, and as a subsequent step, more energy can be coupled into the path. Other atmospheric and flow conditions may require the deposition of energy in one step. In some applications, the deposition of this energy can be: along one or more surfaces; in one or more regions of the atmosphere / flow; and / or some combination of these situations. One or more energy deposition steps may include, but are not limited to, a combination of one or more of the following energy deposition techniques: electromagnetic radiation (from x-rays to microwaves); radio frequency plasma discharges; and electric currents in the form of electron beams, charged particle beams, discharges, and corona discharges; wherein the duration of these energy deposition techniques ranges from continuous beams to ultrashort pulses (e.g., the following pulse widths: attoseconds; femtoseconds; picoseconds; nanoseconds; microseconds; milliseconds; seconds; and longer, up to continuous deposition). These time scales may be different for different embodiments and different modes of energy deposition, where deposition of different modes occurs on their respective time scales. In addition to its own practicality, in some cases, continuous or long-term energy deposition can also facilitate pulsed energy deposition of shorter pulses. In addition, applications involving pulses / phasing / synchronization of certain processes with energy deposition may also include longer pulses and continuous processes.

[0104] The above embodiments of different energy deposition applications and techniques can facilitate applications at various altitudes and flight conditions. It can also be phased / synchronized into different types of spraying techniques under different operating atmospheres / conditions and media, including but not limited to: thermal spray; plasma spray; detonation spray; arc spray; flame spray; high velocity oxygen fuel spray; warm spray; cold spray; and other spraying techniques. Similarly, the above embodiments of different energy deposition applications and techniques can be applied to looms, gun barrels, trains, engines, vehicles, explosion mitigation, ignition, detonation, and other embodiments and applications (within the range of possible operating atmospheres and conditions).

[0105] To illustrate the following explanation, it is best to first look at the example of expansion described Figure 2 and Figure 3Once the energy has been "effectively instantaneously" ("pulsed") deposited in a particular region of air (e.g., along a line or point), the surrounding air is driven outward from the heated region by the expanding shock wave. The surrounding gas is swept outward, leaving behind a hot, pressure-equilibrated region of gas whose density is much less than the initial / ambient density (in some cases, less than 15% of the ambient density, e.g., less than 10%, 8%, 5%, 3%, 2%; or less than 1.5%, with the other 98.5% having been pushed outward), until the shock wave generated by the deposited energy decays / slows to the speed of sound. Once the expanding shock wave has slowed to the speed of sound, it continues to expand outward, no longer pushing air outward, and no longer expanding the low-density region. The low-density region (created when the blast wave expands at supersonic speeds) remains behind, in pressure equilibrium with the surrounding ambient pressure (e.g., it exists as a "bubble" of hot, low-density gas at atmospheric pressure that does not burst and revert back to gas...i.e., it is a region in which the air has been separated). The volume of this pressure-equilibrated underdense region is proportional to the energy deposited in the gas and is also proportional to the ambient pressure (e.g., if the initial atmospheric pressure before the energy is deposited is halved, the resulting underdense volume doubles). Figure 3 An example of this expansion and the resulting low-density region along the surface is shown, which provides an end view of a single straight branch of the discharge, e.g. Figure 2 Those shown in (b), looking along the path of the discharge, obtain the Schlieren image.

[0106] The simplest example of a low-density "bubble" expanding can be seen when energy is deposited at a point in the air ( Figure 4 ), from which the gas expands spherically to open up the low-density sphere ( Figure 5 ).

[0107] When energy is deposited along a straight line, a similar simple geometry occurs ( Figure 6 , 7 and 8). This results in the gas expanding and forming a low-density cylindrical volume (or "tube") centered on the original line / axis along which the energy was initially deposited.

[0108] The fact that thermal, low-density geometries are in equilibrium with ambient pressure and remain so for long periods of time, compared to the fluid dynamics involved, allows such low-density regions (such as spheres and "tubes" in the air and hemispheres and half "tubes" along surfaces and other more complex geometries) to remain "open" long enough to perform the intended flow control.

[0109] One of the simplest ways to envision the benefits of this approach is when looking at a contained explosion. The intuition behind this can be directly applied to other high-speed flow applications, such as high-speed flight and propulsion systems. In particular, when an undesirable pressure buildup and / or shock wave is detected, we are able to (almost instantaneously) reduce pressure and direct gas. These problems in the field of explosion mitigation are the same as those that arise in high-speed flight and propulsion systems, so this initial example can be expanded to apply the basic concepts to a wide range of ultrasonic applications. In one specific example of explosion mitigation, when high-pressure explosion gases are confined between the bottom of a vehicle and the ground, air is prevented from venting from under the vehicle by forming a shock wave in the ambient gas. The longer the high-pressure gas resides under the car, pushing up against its bottom, the more the integrated pulse pushes the vehicle upward. The goal of this application is to vent the high-pressure gas from under the vehicle as quickly as possible, thereby reducing the pressure under the vehicle and minimizing the integrated pulse transmitted to the vehicle. To do this, the gas can be quickly vented from under the vehicle by opening a low-density path along the bottom surface of the vehicle to quickly direct the high-pressure gas from under the vehicle. This can be achieved by incorporating our technology (e.g., a directed energy deposition device) into a ground vehicle to create a low-density path along which a nearby explosion (e.g., beneath the vehicle) can quickly escape, thereby greatly reducing the force and time that the explosion gases push against the vehicle, thereby minimizing the total impact of the explosion on the vehicle. Figure 9 shows an example of the reduction in force and impulse that an explosion may cause when the air density beneath the vehicle is first reduced.

[0110] In order to create a high-speed channel through which the high-pressure gas can pass to escape more quickly from under and around the vehicle, we have arranged a plurality of high-pressure gas flow paths along the surface of the vehicle (such as the Fig.10 ) adds a conductive path (similar to Figure 2 These can be used to discharge high pressure gases in a closed volume almost instantaneously and at high speeds, such as isolators, burners, diffusers, exhaust systems. This can be useful anywhere it is advantageous to quickly mitigate harmful pressure increases.

[0111] One reason vehicles are inefficient at high speeds through the air is that they are effectively accelerating the column of air (from origin to final destination) to a significant fraction of the vehicle's speed. In addition to the significant fuel costs that result, the large amount of energy imparted to the air comes with additional problems such as: a strong sonic boom; a destructive shock wave that strikes behind the nose of the vehicle; and undesirable pressure and heating along the leading edge and stagnation line due to friction generated when accelerating stationary air to match the vehicle's speed.

[0112] In contrast, when the vehicle passes through a low-density "tube" opened by a directed energy deposition device along a long line (e.g., a laser-filament-guided line), the drag is significantly reduced, saving a considerable amount of overall energy consumption. An example of an instantaneously calculated drag curve is Fig.11 . In this figure, a small rise in baseline drag is observed as the cone passes through the higher density gas at the edge of the "tube". As the cone flies through the low density region of the "tube", drag drops sharply. When the cone leaves the low density region and the shock wave begins to reform, drag begins to rise again to the nominal, original / unchanged drag value. In practice, after the vehicle or projectile has propagated through the low density "tube", another low density "tube" can be opened to allow the vehicle / projectile to continue to reduce drag. The exact point at which the subsequent "tube" begins is an optimization problem for a given application. The degree to which drag is allowed to continue to rise before energy is deposited again to generate another "tube" will determine the intensity of the pressure modulation driven at the same energy deposition repetition rate, which will be roughly equal to the vehicle speed divided by the effective tube length (adjusted to accommodate the distance the vehicle / projectile actually travels before energy is deposited again). This modulation will result in an additional source of aircraft noise and can be adjusted by adjusting the "tube" length to avoid vehicle resonances and nuisance frequencies. Each successive "tube" also provides an opportunity to slightly redirect the orientation of the "tube" to guide the vehicle (this will be discussed further below).

[0113] The drag reduction and energy savings when implementing this technology were studied to evaluate the dependence on different parameters such as Mach number, cone angle and “tube” diameter compared to the cone base. These parameters such as Fig.12 , it is understood that the Mach number is referenced to a nominally constant flow. Once energy is deposited upstream, the traditional definition and concept of a uniform Mach number no longer applies. The reason for this result is that the speed of sound inside the "tube" is many times the speed of sound outside the tube in nominally constant free stream. By traditional definition, the Mach number inside the "tube" is significantly lower than the Mach number outside the "tube". In fact, in many cases, the flow inside the tube is subsonic compared to the supersonic / hypersonic flow outside the tube, allowing for significantly different flow fields than those observed when flying through uniform air that is not modulated by deposited energy. Some of these dynamics are described here and can only be achieved by depositing energy into the flow.

[0114] about Fig.12 The results of maximum drag reduction and energy saving (return on energy input) for the various cases shown in are summarized in Fig.13including a drag reduction of over 60%, such as between 80 and 95%, even up to 96%, in the total energy balance and a return on energy invested of over 30 times, such as over 50 or 65 times (i.e., for every Watt or Joule of air deposited in front of the cone to open the low density "tube" along the stagnation line of the cone, 65 times this "invested" energy is saved in propulsive power or energy that would otherwise be required to counter the greater drag experienced if no energy was deposited in front of the cone).

[0115] Some interesting trends are observed in the results, the most basic of which is that opening a larger tube increases drag reduction for all Mach numbers and cone angles. A more nuanced and interesting observation is that the energy effectiveness (i.e., [(propulsion energy saved) - (energy invested)] / (energy invested)) appears to have two regimes. This energy effectiveness describes how much energy is saved from the propulsion system for each unit of energy deposited in front of the vehicle to open the low-density "tube". One region occurs in the narrower cone at higher Mach numbers where the bow wave tends to be oblique / attached. In this region, energy effectiveness increases with Mach number, and the most effective "tube diameter" shifts from smaller diameter to larger diameter in an obvious and understandable manner as Mach number increases. Removing gas along the stagnation line always provides the greatest benefit, and the benefit of removing gas further from the stagnation line is a function of vehicle speed, with increasing benefit obtained at higher Mach numbers. In the lower Mach number region (where the bow wave tends to be a normal detached shock wave), a strong rise in efficiency is observed in the small diameter "tube", which can effectively be used to "pierce" the bow wave, allowing the high pressure gas behind the normal shock wave to be relieved, because the flow in the "tube" can now be subsonic (in the high sonic "tube") and no longer restricted by the bow shock of the cone ( Fig.14 ).

[0116] While effectiveness studies can help identify the energy that can be deposited to achieve optimal performance, it is worth noting that the scale of the effect, and the amount of energy deposited in a particular platform can also be determined based on the platform / vehicle system-considerations that can be accommodated. Even if a smaller diameter "tube" is opened than optimal, better vehicle / projectile performance will still be achieved in terms of increased range and speed, lower fuel consumption, and reduced emissions and noise / sonic boom (some other benefits are documented below). Of particular benefit, significant benefits can be achieved when energy is deposited, even much less energy than the optimal amount. The actual amount of energy deposition capacity and power incorporated into the system can be determined by the amount of space it can accommodate, based on the available size, weight, and power, and how much of these same parameters are improved after incorporating the technology. This flexible, iterative process provides the benefit of incorporating the technology into any system that can benefit from it. Additionally, given that the energy required to open a given volume of low-density gas varies with ambient pressure, a given amount of energy deposited in air will open larger and larger volumes at lower pressures encountered at higher and higher altitudes. This effect also applies to the case where an energy pulse of a given range will open up a larger and larger diameter of the "tube" as the vehicle / projectile climbs altitude. The increased low-density volume at higher altitudes can be used to increase the tube-length rather than increasing the diameter of the "tube"; or to distribute the greater volume over the increase in length and diameter. The increase in "tube" length helps increase velocity, as well as Fig.13 As shown in , a larger "tube" diameter can help maximize efficiency at higher Mach numbers.

[0117] A representative density-contour frame showing the drastically altered flow dynamics caused by flying through a low-density "tube" is shown in Fig.14 The letters A, B, C, and D correspond to Fig.11 D is the resistance in - time marked on the curve (where D represents the moment when the cone travels through the original extent of the "tube", without considering the deformation / extrusion of the tube due to the interaction of the tube with the cone).

[0118] Comparing the difference between the nearly perturbation-free evolution of the density profile in frame A and the subsequent dynamics, we notice several points:

[0119] In normal flight, there is a strong bow wave and associated sonic boom, while flying through this low-density "tube" strongly reduces the bow wave and its associated sonic boom;

[0120] In normal flight, the gas accelerated laterally and forwardly by the cone leaves a low pressure / low density area at the base of the cone, and as the gas moves laterally from the front of the cone, it deposits energy to form a low density "tube", and the gas accumulated around the "tube" recirculates behind the cone and serves to repressurize the base;

[0121] This re-pressurized base reduces base resistance;

[0122] The significantly higher gas density at the base can also provide a level of confinement of propulsion products which can greatly improve the propulsion effectiveness of the exhaust system and increase its effective pulse many times... This is due to recycling the atmospheric backstop propulsion products to utilize their high pressure for a longer time, while the high pressure products simply exhaust unrestricted into the other low density, low pressure base region.

[0123] Phased implementation of propulsion and energy deposition to optimize dynamics

[0124] The embodiments discussed herein may be flexibly applied to improve efficiency and optimize the symbiotic effects / benefits of using / synchronizing various steps / processes, taking into account numerous beneficial dynamics. This may require optimization of many possible parameters, including length size, ignition, air-fuel ratio, timing, repetition rate, chemical process, discharge, laser pulse, microwave pulse, electron beam, valve installation / throttling, etc. Some embodiments include:

[0125] Laser launch: In laser launch applications, one embodiment requires one or more ground-based lasers as a propulsion source, launching at the rear end of a launch vehicle, refocusing the propulsion laser via rear-facing optics to heat and expand the gas or ablation product out of the rear end of the launch vehicle. The laser system and launch vehicle are designed to:

[0126] - Allows some laser energy to be deposited in front of the vehicle to open up the low-density "tube" and reduce drag;

[0127] - sizing and throttling the body and internal paths to allow sufficient propellant air to be heated by one (or more) drive laser pulses;

[0128] - The size of the vehicle body is adjusted to ensure that the modulated gas in front of the vehicle flows around to create a high-density backstop against which the propellant gas can push more effectively;

[0129] - A drive laser pulse is delivered to allow the vehicle to take full advantage of the low density "tube" and propel forward, and then a subsequent laser pulse repeats the process.

[0130] PDE / Chemical Lasing / Pulsed Power: This type of system requires the same type of phasing / timing optimization considerations as listed above. However, in this case, the driving energy is a series of pulsed chemical detonations occurring inside the vehicle. The timing of these detonations can be controlled via properly timed valving and firing, and the detonations can actually drive the processes required to deposit upstream energy.

[0131] Industrial and Transportation Applications: In these cases, similar timing and system optimizations as in the above applications can be applied to achieve the desired level of phasing, with the additional possibility of considering different propulsions, such as electric propulsion, and magnetic levitation. Each element can be timed / synchronized not only to ensure optimal fluid flow, but also to reduce the amount of energy used in onboard systems such as propulsion and levitation systems.

[0132] As mentioned previously, electrical discharge is a possible technology that can enable flexible geometries, which can not only produce significant benefits, but also allow for aerodynamic control and phasing to ultimately allow for precise, powerful and efficient control of the vehicle. If electrical discharge is to be used, a conductive path must be established to allow the current to flow. The use of laser pulses ( Figure 6 ) The ability to "spray" a conductive path and direct / initiate a discharge (Figure 7). A filamentation laser can form such an ionization path with sufficient precision and length to flexibly trace any number of desired patterns.

[0133] Fig.15 An example is shown in FIG. 1 , where a conductive path (108a, b) is created to connect the I Electrodes 106 and 107 intersecting at. Fig.16 and Fig.17 The second example in FIG. 1 describes the actual release device in more detail. In this example, the laser pulse 111 is directed into three separate electrically isolated lens / electrode assemblies 102 ( Fig.17 ).

[0134] Adjustable (122) optical elements 121 focus the different pulses through their respective metal cones 123 to ensure that filamentation starts as close as possible to the tip of the metal cone. This will ensure the best possible electrical connection. The metal cones are electrodes connected to the appropriate poles of a capacitor bank. After the ionization path is created, the capacitors will release their energy along the path. As a result, the electrical energy stored in the capacitors will be deposited in the air along the conductive path in the form of ohmic heating.

[0135] Another embodiment may achieve the desired flow control using several energy release devices arranged / phased to achieve any number of objectives ( Fig.18 and 19 ).

[0136] Fig.18106a, 106b, 106c is arranged on the body 101. The body 101 includes a central element 106a surrounded by an inner annular array of elements 106b and an outer annular array of elements 106c. The entire element array 106 can be used to increase the effectiveness and amplitude of the energy deposition by continuously emitting a single element 106 or a group of elements 106. This can be achieved by using an array of elements 106 to continue to push the fluid 105 outward in a cylindrical shape after the fluid has expanded outward from the central heated core generated by the central element 106a. In this example, when the discharge is performed, it follows an ionization path 108 that completes a separate conductive circuit between elements 106b and 106a. The next set of conductive paths and discharge can then be between 106c and 106a (or 106b).

[0137] In operation, Fig.18 (top), the central element 106a and one or more elements 106b of the inner array may be fired to create a central heated core 160a. This heated core will expand outward, possibly confined by a cylindrical shock wave that weakens as it expands. To add energy to the weakened cylindrical expansion, element 106b may be fired, such as Fig.18 (bottom). After further expansion, the elements 106c of the outer array will also be fired to maintain the strong continued expansion of the heated core 160b.

[0138] A schematic diagram of a similar application involving a linear array of energy release devices 102 is shown in FIG. Fig.19 The energy release devices 102 are mounted on the vehicle 101 to push the inflowing fluid 105 outward along the wings 150 in a wave-like motion by sequentially emitting from the centerline of the vehicle 101 to the innermost energy release device 102a and even to the outermost energy release device 102f.

[0139] As with the connection between the charging unit and the switch, the energy release device 102 will generally be electrically isolated. Fig.16 and Fig.17 As discussed, adjacent energy release devices can be effectively fired simultaneously to form a conductive path 108. The energy release devices 102 can also be fired in pairs in succession to use an electrical discharge to sweep the fluid 105 outward toward the tip of the wing 150. This method of sweeping the fluid toward the wing tip also directs the fluid above and below the wing 150. Environmental sensors can also be included to monitor performance and coupled to the energy release devices to modify different parameters of the energy deposition.

[0140] In addition to drag reduction, there are many associated benefits that accompany the use of the described energy deposition techniques.

[0141] To explore the control forces and moments associated with this technique, 3-D simulations were performed using the Cobalt CFD solver, where a low-density core was generated to impact the vehicle over a continuous range of off-axis positions. The core position was offset by Fig. 20 In these runs, the core was initially positioned coaxially with the vehicle and then slowly moved upward (maintaining parallelism to the cone axis, with no angle of attack). This allowed a quasi-steady-state assessment of the effect of the core as the offset ranged from coaxial (no offset) to an offset of approximately half the base diameter. Fig. 20 We performed this series in order to explore the full range of responses produced by a core aligned with the direction of flight.

[0142] Fig.21 Density, pressure and temperature on the body surface are plotted. Moments and forces are listed as coefficients on the same graph. As examples of different centers of mass, two moments are calculated to obtain stable flight for different payloads / missions. We also demonstrate that an otherwise unstable vehicle (center of mass aft of the center of pressure) becomes stable when flying through this low density core. This is because the higher density gas at the outer edge of the base significantly moves the center of pressure to the rear of the vehicle and behind the center of mass. This benefit of stabilizing an otherwise unstable design can produce greater flexibility in ensuring a stable hypersonic vehicle, eliminating traditional constraints on the location of the center of mass. Other benefits of this technology further reduce design constraints through the use of lower cost materials, allowing for a wider range of performance shells, and significantly reduced slenderness requirements for the body, as well as significant weight reduction due to reduced thermal protection system (TPS) requirements, easier inlet (re)start and greatly reduced control / actuator hardware.

[0143] Analytical upper and calculated lower limits for the generic cone yield control forces ranging from a few Gs to tens of Gs, depending on altitude and Mach number. These upper and lower limits provide useful constraints in evaluating the utility of this technology in different applications. In some embodiments, a vehicle with a 1m base, for example, can employ 480kW of deposited power to produce useful effects over the entire range of Mach 6-20. This power allows: opening a 1 / 5 diameter core before a hypersonic vehicle at 15km; opening a 1 / 2 radius core at 30km; and opening a full diameter core at 45km altitude. If only 10% of this power were available, then we could open a "tube" of roughly one-third the quoted diameter and still gain huge benefits in efficiency, control, and greatly facilitated design.

[0144] One of the limiting factors in hypersonic vehicles is mitigating the thermal effects of sustained hypersonic flight. In addition to reducing drag and enabling vehicle control, our approach also reduces the temperature of the vehicle surface, and the resulting heat generated. This allows for a significant reduction in the TPS weight and special materials required at the leading edge. It also allows for a significant improvement in the performance of the vehicle before material limitations are encountered. Opening a small diameter "tube" in front of the vehicle shows great benefit and helps guide the vehicle, similar to how a pre-drilled hole can help guide a large nail. Nonetheless, it is beneficial to look at the extreme case of opening a "tube" that can fit the entire vehicle. This allows for the intuitive visualization of the vehicle being locked into the "tube" similar to an Olympic bobsled. If the vehicle begins to crash into the "tube" wall, it will experience very strong forces that push the vehicle back to the center. This works in the vertical direction as well as in all other directions, and the vehicle will find a position where its weight is balanced by the upward drag. As a result, the entire body can act as a lifting surface, evenly distributing the associated forces and temperatures. Similarly, the entire body can act as a control surface, because the same phenomena that balance the force of weight will consistently apply a restoring force to restrain the vehicle within the tube. On the one hand, this makes control very attractive as it entails simply directing the "tube" in the desired direction (which can be as easy as directing a starting / leading laser pulse), and the fluid forces will ensure that the vehicle follows, distributing control forces throughout the vehicle body as appropriate. This suggests that further weight and volume requirements can be traded off to help accommodate the hardware required for our approach by eliminating heavy hypersonic actuator / control surface systems. In some cases, each of these flakes has considerable associated volume and can weigh around 20kg. These actuators may require cylinders or power on the vehicle, which have additional weight, volume requirements and risks, and their elimination can be used to offset the requirements of the energy deposition system.

[0145] As mentioned above, the best way to fully exploit the technology described in this article is to design the vehicle completely around fluid dynamics, allowing full exploitation of the many benefits it provides, including drag reduction, flight stabilization, reduced design constraints, enhanced lift / control / intake / propulsion, and significant improvements in speed, performance, range, payload, and fuel efficiency. That said, there are many ways that this technology can be gradually "bought out" on existing platforms by achieving performance gains that cannot be achieved in otherwise optimized systems. Some examples of these include: depositing energy along surfaces to mitigate drag on unavoidable protrusions (e.g., vertical tails, joints, rivets, wipers, seams, etc.), and depositing energy at or in front of the leading edge. In addition to the performance gains these can provide, they can also enable capabilities that would not be possible under other circumstances. A group of applications includes such as Fig. 22As shown, the ability to pierce the tube from the side of the vehicle via an angled shock wave allows for the passage of projectiles / sub-vehicles, as well as optical imaging and communications.

[0146] Shock waves that puncture the primary vehicle in this manner may be particularly interesting in certain hypersonic flight applications, as it can create paths through which images can be more clearly recorded and through which secondary bodies can be carried away from the primary vehicle without the strong interactions they would otherwise experience without the puncturing shock waves.

[0147] Additional examples of high-speed flow control and promotion of supersonic / hypersonic propagation / travel include propulsion and internal flow applications, particularly enabling supersonic inlets and mitigating engine / booster noise, including squeal and other resonances. These involve surface discharges, which we achieve using a variety of electrode types with or without lasers, depending on the specifics. We also apply energy deposition along surfaces and / or in the open air for ground-based applications to improve wind tunnel performance, industrial / manufacturing processes, and transportation.

[0148] For the above-mentioned flight applications, our main concern is to obtain huge gains in terms of capability and efficiency. In ground-based industrial / manufacturing / transportation applications, the restrictions on size, weight and power can be more relaxed. The desire to remotely control uncooperative vehicles also leads us to deposit energy on remote platforms. For this application, the fluid dynamics generated by the deposited energy remain unchanged. However, the main task now is to transfer energy to the remote platform in order to control its power, rather than carefully designing one's own platform to deposit energy into the flow most effectively while reducing size / weight / power requirements. In this case, we use less efficient laser (and / or microwave) energy to quickly / pulse energy deposited on or near the surface of the remote platform, rather than depositing energy via effective discharge. The cost of this energy (in terms of its generation efficiency) is much higher than simply using airborne discharge as the main energy deposition source. However, in return, people obtain the ability to remotely deliver this energy at a distance, so as to exert significant control on remote projectiles / vehicles by locally changing their drag and lift. Fig.23 Schlieren images showing the deposition of laser energy on a remote surface in still and flowing air. In our wind tunnel tests, we were able to measure considerable effects on airfoil lift and drag, which are related to our ability to interrupt the surface flow and boundary layer.

[0149] Rapid / pulsed deposition of energy into a faster-than-fluid stream can respond mechanically and can be accomplished using any number of implementations and mechanisms including lasers, electrical discharges, microwaves, electron beams, etc. to generate a blast wave that dilutes a volume of gas. This energy can be deposited in a variety of useful geometries to dramatically adjust / shape the density of the fluid and achieve tremendous control. This control can result from the strong difference in forces experienced by the body as it interacts with the ambient fluid density compared to areas of significantly reduced density. Common geometries are combinations of spherical and cylindrical low-density areas ("tubes") generated ex vivo, and "hemispherical" and "semi-cylindrical" low-density areas generated along the surface. These geometries achieve significant increases in speed, efficiency, control, and overall performance as a direct result of the strong reduction in drag, heating, pressure, and shock waves when traveling through very low density fluids (relative to ambient density). The most advantageous development of our revolutionary approach will be to design a system around favorable dynamics, by tailoring: inlet; timing; and propulsion to maximize the effects in a full range of ideal operations. Less extensive efforts could also be undertaken by incorporating these benefits into existing or near-term platforms in a way that would “buy” the technology; and / or enable specific capabilities. Such efforts could include: point-by-point mitigation of intense shock / drag / heating / pressure; internal flow control of high-speed propulsion units; inlet for (re)start at lower Mach numbers; etc.; ground testing; manufacturing; ground transportation; and piercing shock waves generated by supersonic / hypersonic platforms to facilitate passage of light signatures and sub-vehicles.

[0150] There are many basic physical mechanisms underlying the various implementations of depositing energy to achieve the significant advances it provides in high-speed flow control. Our approach to revolutionizing high-speed flight and flow control is that in certain implementations, we preferentially move the air to optimize the way it interacts. When energy is deposited effectively and instantaneously ("pulsed") at a point, a spherical shock wave is created that pushes aside a low-density sphere with only 1-2% of the ambient air density remaining. When energy is pulsed along a line, this same expansion occurs to open up a low-density cylinder containing ~1-2% of the ambient air density. The volume of the "opening" we roll up is proportional to the energy we deposit and proportional to the ambient air pressure, so less energy is required to open a given low-density volume at high altitudes (where hypersonic flight typically occurs) than at low altitudes. The benefits of 1-2% of fly-through ambient density over fly-through ambient density are many and include: strong drag reduction; enhanced stability; greatly reduced energy usage; no sonic boom; reduced stagnation temperature and pressure; reduced noise; base repressurization (eliminating base drag and greatly enhancing the propulsion efficiency of the propulsion system); reduced emissions; and a significant increase in flight envelope at each altitude.

[0151] The main effect we exploit when developing new applications is our ability to pulse energy into the air and shape its density. The evolution of large amounts of energy concentrated along point and line sources has been well documented for decades. In his careful computational studies, Plooster provides data on dimensionless units for infinite line sources of instantaneously deposited energy ( Figure 24 to Figure 26 ). In all its figures, energy is deposited at r = 0, and the distance from this origin (in a one-dimensional cylindrical coordinate system) is described by the dimensionless radius λ. In each figure, λ is plotted along the abscissa and represents the true distance r and the characteristic radius R o =(E o / bγp o ) 1 / 2 The ratio of E o is the energy deposited per unit length, p o is the pressure in front of the shock, γ = 1.4, and b is taken as 3.94. Several graphs are plotted on each figure, with numbers above each line. These numbers represent the dimensionless time τ, which is the ratio of the actual time t to the characteristic time t o =R o / a o , where a o is the speed of sound in the ambient atmosphere ahead of the shock wave. All fluid parameters are plotted relative to the fluid parameters in the ambient atmosphere ahead of the cylindrical shock wave, including Fig.24 Pressure in (p / p o ), Fig.25 The radial velocity (u / a o )and Fig.26 The density (ρ / ρ o ).

[0152] The additional utility of these results comes from the fact that Plooster validates them for a wide range of initial conditions (e.g., slight variations on ideal line sources). The long-term dynamics (which are what we are interested in) are essentially the same for initial conditions ranging from ideal line sources to more diffuse sources (e.g., finite-scale deposited energy, involving multiple line sources). It is assumed that the results are robust enough to further cover any method we can envision of depositing energy along the extended region ahead of the shock wave that we want to mitigate / control.

[0153] As the cylindrical shock wave propagates radially outward, Fig.25 The expansion shock wave turns to an acoustic wave at approximately τ = 0.147. This corresponds roughly to the expansion cylinder easing from a blast wave pushing the low-density tube to an acoustic wave, evolving into a characteristic compression and rarefaction (which is at Fig.24As a result, at about the same time, the low-density tube stops expanding rapidly and remains roughly stable from about τ=0.14 to well over τ=6.0. Fig.26 It is shown that as the acoustic shock wave continues to propagate radially outward, the very low density core effectively remains stationary and remains constant from radius λ = 0 to about λ = 0.5. The beauty and utility of such a long, low density cylindrical core is that it lasts a long time and can serve as a low density channel through which a vehicle (and / or high pressure air propelled forward by the vehicle; and / or a buildup of high pressure gas that must be released) can pass efficiently and without resistance.

[0154] The parameters and scales from the Plooster results are used to estimate the energy required to open a low-density tube of various radii in order to perform a parametric study to characterize the effect of the low-density tube on the body in flight. In particular, the simulation aims to show that there are significant advantages in shock and drag reduction when heat is suddenly deposited along the streamlines in front of the bow wave generated by the supersonic / hypersonic cone (in this case, along the stagnation line). The sustained benefits exhibited in the line deposition geometry lead to an extended shock / drag reduction period without continuous energy addition. This allows the pulsed energy deposition mechanism to be repeated in the form of continuous pulses. Once the energy is deposited quickly / pulsatially, the air expands as described above to open the low-density "tube". The two mechanisms that act to erode this idealized stationary low-density tube (as well as a sphere or any other shape formed by the expansion of the deposited energy) are: i) thermal buoyancy; and ii) thermal diffusion. In practice, because these two mechanisms act on an inhomogeneous density distribution, instabilities of the interface and bulk fluid will also appear.

[0155] Similar to a hot air balloon (without the balloon), thermal buoyancy is driven by the buoyancy of the hot, less dense gas inside the "tube" or "bubble". Ignoring viscosity, instabilities, other dissipative forces for objects as light as air, and the extremely low terminal velocity, the highest upward acceleration a low-density gas can experience is the acceleration due to gravity (9.8 m / s 2 ). On the length-scales we are generally interested in, 1 cm can be considered a small but significant motion for a low-density gas. At the upper bound of the unrealistic full gravitational acceleration, the gas will move 1 cm in roughly .05 seconds, which is generally much faster than thermal diffusion will significantly affect low-density features that are quite large (on the order of centimeters or larger). To account for many of the assumptions that make our upper limit too fast, we assume that significant low-density features will remain viable for at least 0.1 seconds. During this time, even a 0.9 Mach vehicle will travel roughly 30 meters, which provides more than enough time for any vehicle of interest to complete its interaction with any low-density structure we intend to create.

[0156] For reasonably sized low-density features (e.g., features a few centimeters or larger in size), the time periods over which these features will dissipate heat by thermal diffusion are much longer than those assumed by the above approximation of thermal buoyancy. Thermal diffusion is essentially caused by the flow of thermal energy along a temperature gradient to eventually reach thermal equilibrium (i.e., heat conducted from a hot gas to an adjacent cool gas). Fig.26 As can be seen in the figure, the interface of the "tube" has a very strong density gradient corresponding to a very strong temperature gradient. This causes heat diffusion at the interface of the low-density "tube". Since this effect occurs at the surface and acts on a small length scale, it is most important for very small features (such as a sphere with a very small diameter or a "tube" with a very small diameter).

[0157] Small low-density features play an important role in the main case that occurs when a very small diameter low-density tube is created by the energy deposited in the air by the laser pulse as a precursor to the pilot / trigger discharge. In this case, the diameter of this low-density tube can be on the order of tens to hundreds of microns or more, depending on the pulse parameters. In this case, we imaged the dynamics of this "tube" and estimated its lifetime to be between 100μs-1ms ( Figure 8 ), and use additional diagnostics to determine these time periods.

[0158] The main role of this very small, low-density "tube" formed by the intense laser pulse is to help guide and trigger the discharge, which can deposit significantly more energy along the way. These discharges follow small precursor channels at a rate of 10 6 The formation of velocities of the order of magnitude of m / s or faster results in a "tube" whose lifetime is easily sufficient to propagate the discharge over tens of meters.

[0159] Another issue that may arise regarding the ionization path and the small "tube" created by the laser is the effect of turbulence. In practice, this has proven to be of little importance for several reasons: i) it takes tens of nanoseconds to propagate a laser pulse; ii) filaments and focused pulses have been shown to propagate not only through turbulence, but also through complex high-speed shock flows / turbulence (examples of which are described in more detail in our section on aerodynamic windows); iii) the development of the discharge is expected to take several microseconds. For these time-scales and dynamics (which are fundamental to using the discharge to form larger operationally useful "tubes"), turbulence does not represent a significant obstacle due to the much slower time period over which it evolves.

[0160] The standard feature we will use to discuss aerodynamic benefits is a low-density core, which Plooster shows extends to about λ = 0.5 ( Fig.26). If we want the radius of this core to be a certain value, then we can use λ = r / R o The definition of energy deposition (E o ), where R o =(E o / 5.34*p o ) 1 / 2 And p o is the ambient air pressure (the constant 5.34 is calculated using a slightly different value of γ than 1.4 to account for water vapor, and also to account for dry air). This gives us the energy per length required to create a low-density core of radius r. First we rearrange to get E o =5.34*p o *R o 2 Then, we can express R in terms of λ and r. o , we get: E o =5.34*p o *(r / λ) 2 The main value of λ that we are concerned with is λ = 0.5, since this is the approximate dimensionless width of the underdense core. The main dimension that provides us with physical information is the actual radius r of the underdense core we want to create. As expected, the energy per unit length required to create a given underdense core is proportional to the square of its radius (i.e., proportional to its cross-sectional area) E o =21.5*p o *(r) 2 When the additional factor of 1 / 2 (squared) is taken into account, the formula for calculating the actual energy / length is

[0161] E o =5.34*p o *(r) 2 .

[0162] To obtain the required total energy, we must simply transform E o Multiply by the length of the heating path. This length is one of the system parameters to be optimized during the testing phase and also plays a role in determining the pulse repetition rate (which must also be optimized). However, we will choose some nominal values ​​here in order to discuss a range of pulse energies and average powers that will allow us to determine some nominal gas heating requirements.

[0163] One way to heat the gas ahead of the vehicle is to prevent "interruptions" in the heat path by creating each new low-density "core" so that its front butts up against the rear of the previous core. However, a way to save power and overall energy deposition is to leave interruptions of unheated air between successive cores. This will allow us to take advantage of some of the time it takes for the bow wave to actually reform ahead of the vehicle. As the bow wave reforms for the vehicle, the next heated core will serve to dissipate it again. The actual distance after the vehicle exits the low-density core that the shock reforms to effectively hinder depends on the shape of the vehicle, the angle of attack, and the flight parameters, but whatever this length is, we can accommodate it by adjusting the energy-deposition length and repetition rate. For example, if we adjust these values ​​to ensure that we create a tube that is the same length as the distance required to establish a new bow wave, we can cut the power requirement for energy deposition in half (because we will have a 1:1 ratio of unheated: heated gas along the stagnation line). A similar phenomenon is exhibited when using point heating ahead of the vehicle. In practice, the optimal ratio of hot core length to unheated length can be determined through wind tunnel testing and more detailed simulations. Our main motivation for testing this parameter very carefully to best exploit it is that it seems to take an exceptionally long time for the shock to "reform" after the vehicle has left a previously low-density "tube". In the conceptual case cited above (which is consistent with the simulations we have already performed), this approach would save us 50% of the energy deposited, allowing us to (by halving the energy input to get the same benefit) double the current efficiency.

[0164] The reason for discussing the above approach to heating an extended path of air is its applicability to shock wave control / mitigation. We will begin by performing a time-resolved study of point heating in the shock wave front and then summarize the experiments we have performed so far in the extended heating region.

[0165] Adelgren et al.'s excellent time-resolved wind tunnel study ( Fig. 27 and 28 ) allows observation of the effect of energy deposition on the bow wave of a spherical model at Mach 3.45. The area of ​​laser heating is roughly a point source, however, it is slightly elongated along the direction of pulse propagation and occurs transversely to the airflow of the tunnel (the beam enters from the side of this tunnel). The resulting heating can be effectively approximated as a point source, and its evolution as an expanding spherical shock wave has been extensively treated. The main feature of this expansion is that the spherical blast wave drives a high-density / high-pressure wave outwards, leaving behind a hot low-density "bubble" at the center. This low-density "bubble" expands to a given size (depending on the amount of energy deposited in the air) and then stops as the acoustic shock wave continues outwards and weakens.

[0166] Fig. 27Approximately 10's of mJ are added to a flow with a 10ns IR pulse. The resulting spherical shock wave is observed to expand as it advects downstream. This low-density "bubble" can be seen to maintain its effectively constant radius as the weakening acoustic shock wave continues to expand. This low-density "bubble" is the spherical analogue of the cylindrical low-density "tube / core" generated as energy is deposited along the line as quantified by Plooster.

[0167] Fig.28 The same geometry of a spherical wind tunnel model placed in the flow after energy deposition is shown. The pressure distribution is shown superimposed on the schlieren image as the laser-induced expansion of the spherical surface interacts with the shock wave of the model. The "circular" line in front of the model is the baseline surface pressure (measured during undisturbed flow), using the model surface as the zero axis. The other line is the surface pressure measured when the picture was taken. The three frames show the transient decompression as a low-density, laser-heated "bubble" stream passes through the pressure ports on the model surface.

[0168] Fig.29 The time evolution of the pressure at the stagnation point (the point with the largest pressure fluctuation) of the model is shown. As the high density of the expanding shock wave first interacts with the model's shock wave and the pressure sensor, a rise in pressure is seen, due to the interaction of the low-density "bubble" with the model and its shock wave. Then, a pressure drop occurs with the subsequent appearance of the low-density "bubble". This results in Fig.30 The outward plume in the bow wave is then disturbed by the rest of the bow wave structure, and the results demonstrate the direct nature of the interaction of the laser-heated gas with the bow wave and flow field of the supersonic object.

[0169] To investigate more effective cylindrical geometries, PM&AM Research has performed some exploratory experimental work to assess what would be needed in wind tunnel experiments, and we have also performed analytical calculations and numerical simulations of shock-tube geometries, where normal shocks are applied to various low-density geometries. These considerations show the great advantages of adopting a tubular geometry. A given amount of energy is deposited at a point in front of the shock wave or along a line in front of the same shock wave (oriented in the direction of propagation of the shock wave). Point heating results in some mixing of the gas and minimal overall effect on the shock. In the case of supersonic vehicles, very little air is pushed out of the path of the vehicle with a geometry that has "point heating". Nearly half of the gas expands toward the vehicle and applies the vehicle's shock wave head-on, while the other half moves away from the vehicle, simply being "attracted" and absorbed by the vehicle's shock wave. In contrast, for the case of sudden line heating, almost all of the cylindrical expansion gas is pushed laterally out of the path of the vehicle (or at least away from its stagnation line). The vehicle is observed to preferentially travel along the low density tube, thereby obtaining a long term reduction in temperature, pressure and density across the leading edge and along the front surface of the vehicle. Furthermore, as the gas moves to the side before the vehicle encounters it, rather than being accelerated forwardly and laterally by the vehicle, the gas is in a recirculation position behind the vehicle. This recirculation re-pressurizes the otherwise evacuated base, thereby not only removing base drag, but also providing a higher density medium that the propulsion system can push, thereby significantly increasing the propulsion effect. These dynamics are Fig.14 Parametric studies of significant drag reduction and energy savings are described in , and the associated papers in that compilation and the references are reported.

[0170] Once a vehicle has fully utilized a heating path (core), another pulsed heating path may be created, resulting in a repetition rate based on the size and speed of the vehicle, as well as the length of the heating core and any unheated space allowed to remain between consecutive cores.

[0171] The technique we propose crucially depends on coupling electromagnetic energy into the air in a precisely defined extended geometry at the shock wave front of this vehicle. Laser "discharges" or "sparks" have been studied with great success since the 1960s. Scaling relations have been obtained for various wavelengths, and contributing mechanisms such as dust and carrier diffusion have also been identified. However, for our application we need more than just a hint of spark in the air. We require that a well-controlled air stream be heated as efficiently as possible. These methods can still be optimized, and one of our main interests is in the ionization and energy deposition caused by the propagation of the laser pulse in the atmosphere.

[0172] The benefit of using UV wavelengths is controlled ionization and energy deposition. Many researchers have used IR lasers to deposit energy in the air, which also has its advantages. One of the benefits is the large range of available infrared laser amplifier materials, another is the ability to heat and ionize intensely. In contrast, the significantly greater amount of secondary light produced by IR absorption results in less energy used to heat the air.

[0173] When comparing UV and IR laser-induced ionization, the actual mechanisms are very different. One major difference is that the higher frequency of UV light enables it to penetrate a larger area of ​​the plasma. This occurs because, in order not to be reflected by the ionized gas, the frequency of the laser must exceed the ionized plasma frequency. Therefore, as soon as the (lower frequency) IR laser begins to ionize the gas, it is soon strongly reflected, scattered, and absorbed by the just-created plasma. The result is typically a single ionized spot that prevents the remaining energy in the pulse from propagating forward; or a series of plasma "beads" along the pulse path. In the case of a single ionized spot, an elongation is typically produced along the pulse path due to various mechanisms associated with the laser-driven detonation wave that propagates backward to the laser. This detonation wave can travel as fast as 10 5 Meters / second in velocity, making it a candidate method for creating an extended heat path in front of the vehicle. Unfortunately, we have only seen reports of relatively short paths (on the order of centimeters), which are best for applications much smaller than what is currently conceivable. However, IR-induced formation of a series of plasma beads has been observed over distances of several meters, and even this "dashed line" can be used to approximate the generation of our desired "extended heat path".

[0174] Another difference in the ionization mechanisms of IR vs. UV radiation is the competition between "avalanche" or "cascade" ionization and multiphoton ionization. The result of their analysis is that shorter wavelengths, shorter pulses, and lower pressure gases all promote multiphoton ionization, while longer wavelengths, longer pulses, and higher gas pressures promote cascade ionization. Cascade ionization occurs at high photon densities via inverse bremsstrahlung. This process is assisted by gas atoms / molecules and accelerates the electron forward after it absorbs the momentum of the laser photon. The momentum buildup of the free electron continues until it has enough kinetic energy to impact-ionize another electron that is bound to the gas atom / molecule. This results in two electrons now absorbing photons and building up their kinetic energy. Continuing these dynamics, a single electron can multiply many times as long as there are enough photons, enough gas molecules to interact with, and enough time for the many steps involved. An estimate of the threshold intensity required to achieve collapse in this manner is:

[0175] I th ~(ω 2 +veff 2 )*(τ p *v eff ) -1 .

[0176] where v eff is the effective rate of momentum transfer between electrons and gas particles (proportional to the gas pressure); ω is the laser frequency; and τ p is the pulse width. Obviously, for lower laser frequency, higher pressure and longer pulse length, I th Lower.

[0177] In the case of multiphoton ionization, higher order collisions occur between non-ionized gas atoms / molecules, and n photons (sufficient to provide the ionization energy) occur. For example, the first ionization potential of molecular nitrogen is 15.5 eV, while 248 nm KrF radiation has a photon energy hv of 5 eV. Since at least 4 such photons are required to provide 15.5 eV, the ionization is considered to be a 4-photon process (i.e., n=4). For 1.06 μm photons, hv=1.165 eV, resulting in n=13, while for 10.6 μm photons, hv=0.1165 eV, resulting in n=134 photon processes (extremely unlikely collisions). An additional rule of thumb can be used to indicate the pulse lengths at which multiphoton ionization will prevail:

[0178] P*τ p <10 -7 (Torr*s).

[0179] This means that at atmospheric pressure, for multiphoton ionization, τ p It should be below 100 ps, ​​while at lower pressures (higher altitudes) longer pulses with more energy can be used.

[0180] As mentioned previously, the cascade ionization that occurs in a long IR pulse will strongly reflect and scatter much of the light in that pulse. For a UV pulse, the ionized region can remain relatively transparent to the pulse, and an extended region of the gas can be ionized. In fact, a region centered at the optical focus of the system can be ionized, extending a "Rayleigh range" (z R ),in:

[0181] z R =ω o / Θ=ω o *f / d=π*ω o 2 / λ (for Gaussian beams).

[0182] where ω ois the beam waist (minimum focal width), f is the lens focal length, d is the lens diameter, and λ is the laser wavelength. Using f=1m and 1.5m lenses, it is possible to ionize an extended path of several centimeters. Using negative optics to reduce the lens f / #, it is possible to obtain an ionization channel of length 2*zR=24cm.

[0183] Comparing the energy required for the two different ionization mechanisms, we see that short UV pulses are more efficient / effective in creating a conductive path. Using 248nm radiation to create the ionized 10 13 e - / cm 3 The diameter is 1cm 2 , a 1 meter long air channel would require only 2.4 mJ of pulse energy. On the other hand, if the plasma reflection problem could be circumvented and an IR laser could be used to ionize the same channel, this would be done almost exactly (2.7x10 19 e - / cm 3 ), and requires a pulse energy of about 6.4 J. Using all of this energy from the laser is prohibitively expensive, since the efficiency of converting electricity to laser light is generally low. Instead, if a laser filament is formed in the air, it couples energy into the gas to open a low-density channel of very small diameter, which can then be used to generate a high-energy discharge, which will make it more efficient than lasers in coupling energy into the air. The energy from the discharge is also cheaper to generate than energy from lasers. To mix and match the most useful elements of each deposition method, we note the enhanced ionization of air by 1.06 μm laser pulses in the presence of preionization. One possible exploitation of this phenomenon is to use ionization from a UV seed laser to indicate where IR energy-deposition occurs, strategically coupling IR radiation into the air. To facilitate this process, UV light can be generated as a harmonic of the IR light. In addition to the ionization generated by the laser pulse conducting electricity, it is significant that it also couples energy into the air and generates a low-density channel. In this low-density channel, charges can be more easily accelerated, resulting in easier formation of a discharge along the path of the ionizing laser pulse. The short time periods involved also enhance the contribution that metastable species, such as metastable oxygen, may have in forming the discharge. A potential alternative method of coupling less expensive energy into the pre-ionized and subsequently rarefied gas region is to use microwave energy. Research into such coupling is currently in its early stages.

[0184] Laser pulse technology has significantly broadened our options for heating extended paths, with the main development being the formation of filaments. Many researchers have studied filaments, and most of the work has been on IR filaments. UV filaments have been proposed to overcome / complement many of the disadvantages of using IR wavelengths. According to theory, a UV filament could be kilometers long, contain several joules of energy, have a radius of about 100 μm, and have a wavelength of 1x10 12 e - / cm 3 and 1x10 16 e - / cm 3 ionized gas between them. In contrast, an IR filament cannot contain more than a few mJ of energy, and once this energy is exhausted (consumed by propagation), the filament breaks and diffracts very strongly. Brodeur has proposed, and later showed by simulation, that a large fraction of the filament energy intermittently goes to a larger penumbra diameter of 1 mm as it diffracts from the more highly ionized core. This remains a reservoir for the formation of new filaments as earlier filaments break.

[0185] Comparing UV and IR, it has been shown that UV filaments lose approximately 40 μJ / m and gain approximately 2x10 15 e - / cm 3 ionization. This is reportedly 20 times the ionization measured in IR filaments, resulting in a 20-fold increase in conductivity. Another advantage is that UV filaments do not lose energy through the "conical emission" of light and therefore use their energy more efficiently to ionize and heat the gas, which makes the formation of the small, low-density tube that promotes discharge formation more effective.

[0186] Fig.30 Theoretical results are shown in , demonstrating an oscillatory exchange between field strength and ionization on length scales in the meter range. Given sufficient initial energy and pulse width, these oscillations occur in an envelope that can extend over several kilometers. Fig.30 and Fig.31 In both figures, the vertical scale is in μm and the horizontal scale is in meters. Fig.31The lines in the graph representing the boundaries of the filaments with an initial power of 160 MW effectively show that there is no diffusion of the beam, and the predictions of the model agree very well with the experiment. The similarities to IR filaments in the oscillations between ionization and photon density suggest potentially interesting interactions between arrays of filaments. In this case, the individual “penumbra” fields will overlap, allowing crosstalk or energy exchange between arrayed filaments. Such an array would be created by constructing the initial beam profile to have local intensity maxima at certain points to nucleate the filaments. An array of filaments with lengths of meters would be an effective way to deposit energy in a very focused and controllable manner. One possibility to couple the two is to use an array of UV filaments as a waveguide for the IR light. The IR light intensity may be lower than that required to ionize the gas, but the ionized regions between the UV filaments will help couple the IR radiation to the gas. This would allow the IR radiation to be efficiently coupled to the gas without the otherwise necessary high field intensities. This complementary approach could mitigate the (typically too strong) IR ionization and prevent the associated waste of bright light generation. The low-density channels created by the UV filaments could also guide the IR light more efficiently.

[0187] Our initial focus on scaling up thermal deposition in a cost-effective manner is to use low-density regions created by laser-ionized gases or filaments to nucleate and direct the discharge.

[0188] This is performed by directing an 80mJ, 1ps laser pulse through two ring electrodes to create an ionization path between them. The electrodes are held at a voltage below their normal discharge voltage, and when the laser ionization path generates a low-density path between these electrodes, it nucleates the discharge and is directed in a straight line ( Fig.32 ). This precursor laser pulse can reduce the threshold breakdown voltage by 25-50% (which is typically 20-30 kV / cm at sea level). The enhanced breakdown is caused by a number of mechanisms, mainly benefiting from the small areas / channels of low density opened up by the small amount of energy deposited by the laser pulse itself. Longer filament initiated / guided discharges have been demonstrated, generating intermediate lengths of 2 m, as shown in Figure 7.

[0189] We have also connected through Figure 6 As shown, multiple paths generated by multiple laser pulses generate discharge (Figure 33).

[0190] To further implement this technology realistically on a real platform, the filamentation laser is propagated through an aerodynamic window. The aerodynamic window has historically been used to "separate" two regions between which the high intensity laser energy must propagate. This is necessary if the laser intensity is high enough that the energy cannot pass through the window without catastrophic destruction of a solid window and beam. Rather than a solid window separating the different regions, the aerodynamic window separates them with a lateral flow of air. High pressure air is expanded through a nozzle / throat to create shock and rarefaction waves on either side of the window. This establishes a strong pressure gradient across the window (transverse to the direction of the flow). If the corresponding high and low pressures match the external pressures on either side of the window, then little or no flow occurs over or into / out of the window if a small hole is drilled to allow the laser pulse to pass (see Figure 34).

[0191] The use of an aerodynamic window allows for a complete decoupling of the energy discharge device from any external atmospheric conditions. Applications can range from fixed applications at sea level to supersonic / hypersonic applications at various altitudes. In fact, the flow within the aerodynamic window can be adjusted to varying external conditions (e.g. external pressure variations caused by altitude and vehicle speed / geometry).

[0192] In our demonstration, pulses propagated through the vacuum side of the pneumatic window (Figure 34) to the surrounding atmosphere formed filaments. They have also been propagated from the atmosphere through turbulent / shock flows within the pneumatic window to pressures ranging from 4 torr to 80 torr. At these low pressures, the filaments defocused and left the low pressure chamber through a solid window. They were then reported to regenerate into filaments under atmospheric conditions. These geometries demonstrate the robustness of UV filaments, eliminating concerns that they are too fragile to be implemented and deployed in any kind of platform, including supersonic / hypersonic applications.

[0193] Similar to our technique of coupling discharges into laser plasmas, microwave energy is also more cost-effective than laser energy as a cost-effective method of depositing larger amounts of "lower cost" energy into air, and can similarly be used as a cost-effective method to increase the energy deposited into air along the plasma geometry set up by the laser. Two related advantages of using microwaves to more efficiently couple energy into air through a laser-generated plasma are: i) no closed circuit is required to couple the energy; and ii) the energy can be deposited ex vivo, which is advantageous at higher speeds. Combining multiple energy deposition techniques can provide greater flexibility, including laser pulses and / or filaments of various wavelengths, discharges, microwave pulses, and / or electron beams, among others. Some conceptual coupling geometries and results are reported, and we are also exploring the details of coupling short microwave pulses into laser plasmas and filaments.

[0194] Table 1 summarizes the conceptual time scales involved in each step of the conceptual application to achieve the desired aerodynamic benefit for the various individual mechanisms occurring in succession, to provide the appropriate context in which to take into account the reaction times of any sensors and electronics used in the overall system. In this table, the two mitigation mechanisms, thermal diffusion and thermal buoyancy, are indicated compared to the areas where they dominate. For the very small "tube" created by the filament itself (which the discharge can form), thermal diffusion is the fastest mechanism for scrubbing the hot, low-density tube. In this case, the time scale on which the tube survives exceeds the few microseconds required to form the discharge. For the larger "tube" created by the large amount of energy deposited by the discharge, thermal diffusion (which acts at the interface of the low-density and high-density gases defining the tube) is negligible, where the regulating mechanisms that destroy the tube are thermal buoyancy and instabilities, which also do not significantly affect the tube for even a millisecond, which is sufficient for even the slowest vehicle to propagate through the tube. The time scale required to actually open the tube is also estimated, and this tube opening speed is fast enough, even for the fastest vehicles, to obtain the benefits of flying through the tube. There are likely to be many applications involving flow control by deposition of energy on a surface (usually without the need for a laser) where the applicable time scale remains roughly the same. Table 1 does not address the time scale for coupling microwave energy into a laser plasma because this time scale has not yet been definitively quantified.

[0195] Table 1: Basic time scales for conceptual applications

[0196] Ultrashort pulse lasers form plasmas with a density of ~10 13 -10 16 e - / cc filament

[0197] a. Speed ​​of light: (3x10 8 m / s)→1ft / ns

[0198] Electron recombination: transfer energy to (i.e. heat) the gas

[0199] b. Plasma reorganization in ~10ns (up to 100ns)

[0200] Small-scale low-density channel opening (enabling discharge)

[0201] c. Discharge formation is opened within tens of nanoseconds (due to thermal diffusion lasting 100μs to 1ms, interruption begins)

[0202] d.10 6 -10 7 m / s→10ft / μs

[0203] Discharge duration: several μs

[0204] e. Current flows & Ohm heats the gas (straight ball lightning)

[0205] Large-scale low-density channels open

[0206] f.10's-100'sμs (10's ms thermal buoyancy causes disruption, which enables low drag propagation over a range of 10's meters for a vehicle traveling at 1km / s)

[0207] The total time of the whole process is ~ equal to the time to open the large tube (~100μs)

[0208] g. Fast enough compared to flight speed (a vehicle traveling at 1-3 km / s can only travel 10-30 cm in the time it takes to open the large tube, while this vehicle can travel 10's meters in 10's ms)

[0209] Hardware and latency are important factors to consider when discussing various applications, and are indicated here to emphasize their consideration when determining the timing chain for a specific application, as these hardware timescales must also be considered (in addition to the basic timescales summarized in Table 1) to perform realistic estimates and build a working system. For example, when mitigating the inlet non-startup problem, the physical timescales are important, however, the sensors, signals, and any processing (which we prefer to avoid by adopting a pure hardware solution when possible) will add latency (especially pressure sensors, as other hardware items are generally faster). A specific system example is stepped through to highlight the fast response time of our flow control method compared to other existing technologies.

[0210] We have discussed some of the finer points of energy deposition into the flow, including mechanisms for coupling lower cost discharges and / or microwave sources. The purpose of addressing some of the details is to help provide more physical / intuitive understanding of the dynamics, and to drive future development of this broad set of revolutionary technologies that could fundamentally change the way we fly.

[0211] In the past, methods of reducing drag by depositing energy in a manner that causes a fluid, such as air, to be moved laterally out of the path of an object, thereby promoting the forward motion of the object, have been disclosed. In various other applications, energy deposition for controlling flow has been further disclosed [citing Kremeyer patent]. In one drag reduction embodiment, energy is deposited to create a low-density region through which an object propagates. The extent of this low-density region is limited, and additional low-density regions can be created as the object propagates so as to continue the benefits of propagating through the low-density region. If these regions are created in close proximity to each other, an almost continuous low-density region can be generated to enjoy nearly continuous benefits. Since the low-density region requires energy to establish, it is more advantageous to utilize its optimal benefits. The definition / goal of "optimal benefit" can vary depending on the application and relative value of the relevant benefits and resources. These benefits can include, but are not limited to, speed, range, energy, weight, acoustic signature, momentum, time, power, size, payload capacity, effectiveness, accuracy, maneuverability, and many other possibilities. These benefits vary from application to application, and specific parameters must be adjusted for a given embodiment and its specific conditions and goals. We have disclosed here a concept of tailoring specific implementations and combining pulsed energy deposition, synchronized with other pulses or single events in a manner that optimizes the desired benefits. Some examples are given below.

[0212] Synchronized pulse operation for high-speed vehicle / projectile applications

[0213] In the above disclosure, the dynamics of a vehicle traveling through a low-density tube has been described, demonstrating a pulse effect that begins as the vehicle enters the low-density tube. The effect lasts for a certain period of time, which depends to some extent on the length of the low-density tube and the speed of the vehicle. Fig.14 AD are arranged in sequence with their approximate relative times marked on the inset drag trace. One aspect of the dynamics to note is that the drag on the tapered concept vehicle increases slightly as it passes through the higher density air sheath surrounding the low density tube created by the deposited energy lines. This higher density sheath contains gas that pushes outward in a cylindrical shape in order to rarefy the low density tube. Upon entering the low density portion of the tube, the drag experienced by the vehicle is greatly reduced. At time D, the vehicle has penetrated the original length of the tube, and it is apparent from the drag curve that steady state flow conditions require additional time to reestablish. Another point to note is that the bow wave and associated far field sonic boom appear to be completely eliminated as the vehicle passes through the low density tube.

[0214] Besides these extremely interesting aspects, a key aspect of the dynamics is the pressure distribution around the vehicle, which is caused by the redistributed density.

[0215] As in Fig.14As observed in A, before the vehicle penetrates the low-density portion of the tube, the density at the base of the vehicle is very low. This rarefied low-density / low-pressure region at the base of the vehicle is a result of typical supersonic / hypersonic fluid dynamics. This region is the result of the gas in the path of the vehicle being pushed forward and sideways from the vehicle, similar to a snowplow throwing snow out of the path of the snowplow (leaving an area without snow accumulation). The dynamics are also similar to the dynamics we use to create low-density regions when we deposit energy. In both cases, the gas is pushed outward, leaving a rarefied region. However, in contrast to the typical case of supersonic / hypersonic flight where there is no energy deposition in front of the vehicle, the mechanical energy imparted by the vehicle to the upstream gas creates a high-pressure region and shock wave in front of the vehicle, applying a so-called wave drag with high pressure behind the shock wave that pushes the vehicle backward. Moreover, the vacuum left after the vehicle mechanically pushes the gas outward from the front and side of the vehicle creates an evacuated low-pressure region at the base of the vehicle, thereby harvesting the base drag that further pulls the vehicle backward. Both of these forces are greatly mitigated when we deposit energy in front of the vehicle along a line to push gas laterally out of the path of the vehicle. The extent to which these forces are mitigated depends on the amount of energy we deposit per unit length in front of the vehicle. Removing gas from the front of the vehicle reduces the wave drag, and also minimizes the gas that is mechanically pushed outward when the vehicle is pushed (which also minimizes the sonic boom). As mentioned above, base drag is generally created by the low pressure area left behind when the vehicle or projectile mechanically pushes gas outward from it. In contrast, when the gas in front of the vehicle / projectile is pushed to the side by depositing energy ahead of the vehicle / projectile, then left behind the vehicle / projectile, rather than "throwing" a low density area out the side to create base drag, this gas can just sit outside of the path of the vehicle in a more stable manner; or if it is in the path of the vehicle, it will not be subject to the mechanical acceleration of the vehicle itself, resulting in less lateral momentum imparted to the gas by the vehicle / projectile. The less lateral momentum imparted to the gas, the lower the sonic boom, and the less base rarefaction. With the gas in front of the vehicle to the edge of the vehicle completely removed (e.g., opening a tube with the same radius as the vehicle), the high density area of ​​gas pushed out of the low density tube is now most fully recirculated behind the vehicle to repressurize the base. This repressurized base significantly contributes to the overall drag reduction effect of the vehicle, which can be combined with the pulse propulsion process to maximize the overall efficiency of the vehicle. In the past, we have mainly considered the aerodynamic characteristics of the vehicle. Considerations for propulsion, and indeed for the pulse propulsion process, still allow for greater optimization of the vehicle, especially in the compressible flight regimes, most notably the supersonic and hypersonic regimes, as well as the high subsonic / transonic regimes.In one embodiment, the optimal benefit is to design the aircraft around this concept so as to make the simplest and most cost-effective vehicle possible. Other optimal benefits may include those listed previously, such as the shortest possible flight time. In addition to depositing energy in front of the vehicle to reduce drag and guide the aircraft, we can also synchronize these dynamics with a pulse propulsion system (which is more efficient than stable propulsion, such as a pulse detonation engine, as well as other pulse propulsion options) to achieve the desired effect (or effects). Other and / or additional processes may also be synchronized with these dynamics to further benefit, and we will first consider pulse propulsion using an embodiment of a pulse detonation engine. Fig.18 Two conceptual representations of pulse detonation engine dynamics are depicted.

[0216] A very important aspect of pulse propulsion is the pressure at the outlet / exhaust face of the system. In the typical case of very low base pressure, resulting in very low pressures at the outlet / exhaust face of the propulsion system, the detonation tube (the combustion part of the pulse detonation engine) fills quickly with reactants. Since the back pressure is very low, the high pressure part of the propulsion cycle (exhaust time) does not last very long either. The typical propulsion cycle time depends on the design of the engine, and the geometry can be varied to change the cycle time. Other key factors that affect the cycle time are: the mass flow rate at the inlet (more specifically, the mass flow rate and pressure at the inlet face of the detonation tube, which is usually opened and closed with a valve), which affects the velocity at the tube filled with reactants; and the pressure at the outlet / exhaust face, which affects the residence time of the high-pressure detonation products and the thrust they produce. Under typical flight conditions, these pressures at the inlet and outlet faces are determined by flight parameters. When we add the above-mentioned energy deposition dynamics, it is possible to change the conditions at the inlet and outlet of the pulse detonation engine very advantageously.

[0217] The basic approach would be to time the energy deposition pulses in front of the vehicle with a propulsion pulse so that air from the front surrounds the vehicle to re-pressurize the outlet (or outlets) of one or more propulsion units, with the higher density air providing enhanced confinement of the exhaust gases coinciding with the propulsion portion of the pulse propulsion (e.g., pulse detonation) cycle. In other words, the dynamics involve synchronization / phasing / timing of the increased base pressure (i.e., increased pressure at the outlet / exhaust face of the propulsion unit / units) resulting from the energy deposited in front of the vehicle to optimize the propulsion / thrust generated by the one or more pulse detonation engine cycles. The additional confinement provided by the increased density at the outlet (or outlets) of the propulsion unit or units would significantly increase propulsion effectiveness during unboosted operation.

[0218] Similarly, as the bow wave of the vehicle reestablishes (after having been mitigated by the low density tube), the establishment of a low base pressure can be synchronized / phased / timed to facilitate the flushing and filling phases of the propulsion cycle. The lower base pressure will allow for faster flushing of combustion products and filling of new combustion reactants. This can be done in air-breathing or rocket mode (where oxidizer is carried on board and no outside air is used). Rocket mode can be applied when maximum power / thrust is required, regardless of external conditions, particularly when the valuation of speed and power is greater than the reduced vehicle weight and volume.

[0219] In the case where the propulsion process is exhalation, we can also time the energy deposition to preferentially direct a certain amount of air exhausted from the front of the vehicle to the inlet. All of these details are timed together and dictated by the design of the vehicle, which can be optimized to take advantage of various dynamics. The matching of the repressurization period with the maximum exhaust pressure period is indicated by changing the length of the low-density tube and the length of the PDE we create, respectively, and adjusting the timing between the two, and all of these and other parameters can be adjusted to optimize the performance of the vehicle for a given application. Similarly, the inlet can be designed to allow air to enter to feed the propulsion cycle, which will be specified to some extent by the earlier matching conditions. For added flexibility, we do not have to match the same cycle (for example, if the high-density gas plug of the repressurization base around the body travels too slowly due to skin friction, we can adjust the size of the vehicle and perform dynamic timing so that the high-pressure period we create at the base coincides with the thrust generation phase of a PDE cycle, and does not necessarily start when the low-density tube starts). For example, if we want to have shorter low density tubes or shorter engines (or shorter detonation tubes in the engine) by applying a method to create multiple engines that operate sequentially like a Gatling gun (or in whichever mode provides the most favorable forces and dynamics), further flexibility can be provided. Each detonation tube can have its own inlet, which can be provided by similarly applying electrode rings in sequence, which in turn arc to the center electrode. These discharges create a laser-induced / guided V-shape, which not only reduces overall drag by removing air in front of the vehicle, but also compresses the air between the legs of the V so that the air is sucked into a smaller inlet than would otherwise be required. In order to provide the engine with higher pressure and oxygen at its inlet, the inlet will be fired in the same sequence as the detonation in the multiple engine tubes, but delayed by a certain time determined to best meet the benefits of base-repressurization, and the presence of high density gas at the inlet, and the entire engine cycle designed into the platform. It is common to think of a valve in the engine that opens when air is sucked in and closes during detonation. By adding a rotary valve (e.g., following the same spirit of the Gatling gun concept), its rotation can be adjusted / moved to appropriately facilitate the advancement sequence. Such a rotary motion can be similarly employed to facilitate the generation of laser filaments.

[0220] The timing of upstream energy deposition and engine cycles can affect system design and operating parameters to adjust the size of the engine tube length and diameter, as well as the number of engines specified themselves, so as to result in a propulsion pulse cycle time that is commensurate with the energy deposition cycle time. These times can range from less than 1 ms to several ms. In particular, a relevant range can be for short-line (theoretically in the range of 10 cm to 40 cm) energy deposition at high speeds (theoretically in the range of Mach 6 to Mach 12), resulting in cycle times from .025 ms to .2 ms. In order to match these energy deposition cycle times with comparable propulsion cycle times, it is possible to use shorter engine tubes with appropriately adjusted diameters, as well as an appropriate number of such tubes to accommodate the matching. In order to take advantage of the high and low pressure cycles caused by the drag reduction tube dynamics, the tube can also be adjusted to generate a propulsion pulse that is shorter than this cycle time. If the timing requirements become overly restrictive, the complete matching of energy deposition and propulsion cycles can also be abandoned. In the case where the duration of the propulsion pulse matches or does not match the base pressure cycle of the energy deposition, an additional variable that helps achieve the best possible match is the degree to which the air is modulated into the potential inlet array, potentially driving the potential engine tube array. There is also the flexibility to discharge each of the potential multiple engine tubes in its own separate exhaust plane for better dynamic matching; or to have the engine tubes discharge into one or more common exhaust planes. At the other end of the potential cycle times, longer cycle times can be produced when flying at lower speeds (e.g., from Mach 0.8 to Mach 6) and using longer deposited energy tubes (e.g., ranging from 1-10m), resulting in drag reduction and base pressure cycle times ranging from ~40ms to .5ms (matched to propulsion cycle times). This range of longer cycle times can be matched using a smaller number of engine tubes (including a single engine tube), with the details depending on the design and operating conditions of the vehicle and engine (one (or more) tubes).

[0221] Similar to the use of a discharge directed and initiated along a closed path using ionization by a laser pulse (e.g., a laser filament), energy can also be deposited further in front of the vehicle using more remote deposition techniques such as deposition of microwave energy, with the deposition seeded / facilitated by creating an ionized area in front of the vehicle, again, potentially using a laser plasma. This microwave energy can also be preferentially directed upstream with a laser plasma, such as a laser filament. High microwave energies generated by sufficiently short microwave pulses can also be used with or without seeding to increase the coupling of microwave energy to the air. Three benefits of depositing energy further upstream are: i) no return path is required, thereby simplifying and reducing the energy investment in any guidance / seeding path or area; ii) the excitation volume has more time to expand, which is advantageous at very high Mach numbers (e.g., Mach 9-25), although laser-guided discharges still show great benefits at these speeds; iii) for ionization of the shock wave, which typically occurs above Mach 12 or 13, the more remotely focused microwave and / or laser energy can penetrate the ionized shock wave, thereby alleviating any difficulties that may arise from the interaction of the discharge with the ionized shock wave. This consideration when using discharges requires that the laser path be more favorable than other possible paths containing various ionization levels under ionization Mach number conditions.

[0222] In addition to depositing energy in the air in front of the vehicle, in order to condition the air encountered by the vehicle (and drawn into one (or more) inlets for air intake applications), surface discharges may also be employed in phasing / synchronization of energy deposition, both internally and externally, to control internal and external flows to enhance the propulsion effect, performance, control and / or overall efficiency of the vehicle.

[0223] Similar to the high-speed aircraft / projectile application disclosed above, energy can be deposited in front of a high-speed ground vehicle and phased / synchronized / timed with various other operating processes to optimize certain benefits. In the case of an electric high-speed train, much of the infrastructure already exists to deposit energy. Electrical pulses have been directed to the track to suspend, propel, monitor and / or control the ground vehicle. This existing infrastructure greatly facilitates the use of grid power to provide the energy that must be deposited to create the low-density area in front of the vehicle to significantly reduce drag and facilitate higher speed operations. In some embodiments, laser pulses will not be required because the track already exists to guide the vehicle, thereby defining the path of the vehicle. High energy discharges can be used and open low-density areas or tubes that precisely follow the track, along the path of the vehicle, depositing energy in front of the vehicle. The size of the low-density tube can be controlled to generate a desired drag reduction level while also contributing to the aerodynamic stability of the ground vehicle. When depositing energy in front of the aircraft, the diameter of the tube will be determined by the energy deposited per unit of length, as well as by the ambient atmospheric pressure. In the case of energy deposited along the ground or along a track, the ideal shape of the low-density tube is a cylinder centered on the line of deposited energy (when depositing energy along a line in the open air), unlike when depositing energy along a line on an ideal flat surface where the shape of the tube would be a semi-cylinder.

[0224] If the half cylinder were replicated as a reflection off an ideal flat surface, it would look like a full cylinder, the same as if deposited in open air. Because only half of the cylinder is rarefied, to open the half cylinder along the same diameter of ground (along the track) only half of the energy of the full cylinder would be required in open air. In reality, the deviations from the ideal will be caused by the geometry of the track from a perfectly flat surface, and by the interaction of the shock waves generated by the deposited energy with the ground and the real geometry of the track. However, the low-density volume that opens up in front of the vehicle will be approximately the same as the volume of an ideal half cylinder on an ideal flat surface, and its actual shape can be adjusted and controlled by shaping the track. In fact, the degree of insensitivity to the details of the deposition allows a number of advantageous features to be incorporated into the process. One of these features is the ability to deposit energy in the discharge (to create a low-density tube) in the form of multiple sub-pulses, rather than a larger single pulse. This can reduce the size / capacity of many circuit elements and conductors, and allow for better utilization of existing circuits, such as when multiple propulsion and levitation magnets are engaged at a given point in time or along the track, then energy from these individual circuits can be individually redirected / recirculated and fed forward to drive one (or more) discharges along a section of the track, thereby obtaining the same benefit as if all the energy were collected and combined from propulsion and levitation circuits that were engaged close in time or overlapped. Each of the drive circuits for these propulsion and levitation circuits can also be configured to drive the discharge circuits independently, rather than being combined first. As disclosed in earlier patents and incorporated by reference, the conductive paths along the track (along which the discharges are generated to deposit energy to expel air) can be composed of slightly better conductive paths than the less conductive medium in which they are embedded (such as concrete or other potentially poorly conductive track materials). Slightly preferentially conductive paths can also be composed of "dotted" conductive materials, such as sheets of electrode material embedded in less conductive track materials. Similar to the flexibility provided by temporally splitting the discharge into multiple separate discharges that will merge into a single low density tube, the discharge can be further composed of spatially distinct discharges that can merge into a single arched low density tube. Such spatial separation can be performed as an example between different sheets of electrode material, where different portions of this "dotted line" are independently excited. The spatial separation can also occur in the form of discharges that travel along approximately the same length but follow separate paths (a variation of which is to deposit energy along multiple spatially distinct but parallel paths from which the low density tubes expand and coalesce to form a larger arched low density tube. More realistically, such separate paths may not be ideal and are not necessarily completely parallel to each other, with slight variations in their respective paths.This flexibility in spatial and temporal frequency can be further combined by depositing energy along different paths at different times, provided they are close enough in time and space to allow them to coalesce into a low density tube in the shape of an arch. In addition to accommodating a large number of natural fluctuations, this flexibility reduces tolerances and also allows for more complete utilization of existing circuits without having to add unnecessary circuits to combine energy from multiple feeders (e.g., those feeding multiple propulsion and / or levitation coils) or recycle / recover energy from the multiple propulsion and / or levitation coils. Another feature is the ability to place small canopies over one or more preferred conductive paths in the less conductive track material, thereby protecting one (or more) path(s) and one (or more) discharge(s) from debris, weather, environmental contamination (e.g., bird droppings), etc. Gutters can also be installed to prevent rainwater from accumulating without causing detrimental effects on the opening of the tube, and a canopy can be installed over the entire track as further environmental protection, which canopy may have multiple layers, perforated in a manner to minimize reflections, and screens or meshes may also be installed around the track as needed to exclude wildlife. A further operating feature may be the cleaning of the track by the passage of the vehicle, such as by dragging a light brush just behind the vehicle. The discharge itself will also help to clear any potential contamination.

[0225] For propulsion, electrically propelled high-speed ground vehicle designs (e.g., magnetically levitated vehicles) may use linear synchronous motors, where power is supplied to windings on the rails (i.e., on the "active rails"). For propulsion and levitation purposes, the inductive energy stored in the loop / circuit must be dissipated after the electromagnets are energized. Great effort is usually spent to minimize arcing caused by this energy dissipation, due to the large voltages generated after the train passes, which have a natural tendency to generate strong arcs, which have historically been seen as a problem to be mitigated. Instead, this energy can be effectively used by depositing it in front of the vehicle to remove air from the front of the vehicle, rather than dissipating it in circuit elements designed to consume this energy over a longer time scale. In addition, since at high speeds, the propulsion energy required to propel the vehicle is of the same or greater magnitude than the energy required to push the gas in the path of the vehicle, the power and energy delivered to the inductive propulsion element are already appropriately sized to deliver the pulsed electrical energy required to reduce vehicle drag (this available power, energy, and circuit from the propulsion element is enhanced by those from any levitation element). Converting the inductively stored electrical energy into a discharge suitable for drag reduction and stability enhancement will require some kind of circuitry that is unique to the overall vehicle and power transmission / conversion design, and such circuitry can be mounted on each inductive magnet along the track; or it can be contained on the actual vehicle, saving cost. A hybrid approach can also be adopted, where part of the discharge circuit is distributed along the track, and some part of the discharge circuit is contained in the vehicle, ensuring that during normal operation, discharge only occurs in front of the vehicle. This can serve as a beneficial and natural safety feature. In terms of energy, for lower speeds, such as 100m / s-280m / s, energy pulses can be deposited in the form of discharges in front of the vehicle to allow greater speed and stability of propulsion pulses used to move the vehicle forward against friction and drag forces of approximately 50% to 300% in magnitude. At higher speeds, e.g. 250m / s-600m / s, energy pulses may be deposited in the form of discharges in front of the vehicle to allow greater speed and stability of propulsion pulses of about 20% to 200% of the magnitude used to move the vehicle forward against friction and drag. At still higher speeds, e.g. 450m / s-1200m / s, energy pulses may be deposited in the form of discharges in front of the vehicle to allow greater speed and stability of propulsion pulses of about 15% to 150% of the magnitude used to move the vehicle forward against friction and drag. In one embodiment, the hardware along the track is expected to be standardized and capable of generating the same maximum energy propulsion (and, where appropriate, levitation) pulses, as well as generating discharge energy in front of the vehicle between propulsion magnets.Given this ample power supply, there is always enough power to deposit energy in the form of discharges in front of the vehicle that provide higher speed and stability. With this flexibility, the energy of the discharge pulses can be adjusted to optimize the efficiency of the vehicle; and / or facilitate higher speeds that would not otherwise be possible; and / or increase the stability of the vehicle. The energies and energy ratios will be adjusted according to the vehicle and circuit configuration, as well as its operating conditions.

[0226] High-speed trains do not need electric propulsion or magnetic levitation in order to benefit from depositing energy ahead of them to reduce drag and improve their stability and guidance, and any high-speed ground vehicle can benefit from these dynamics. Electric-propelled vehicles are particularly suitable for incorporating this technology, including magnetic levitation. Regardless of the propulsion or levitation method, since aerodynamic forces are used to center the vehicle in the low-density tube created along the track, this technology serves to increase the stability, control and simplicity of the vehicle, as well as the speed at which it can travel when the track deviates from the straight path.

[0227] When weaving a fabric in a loom, it is necessary to somehow push the weft (or filler or yarn) through the warp in order to form the braid. A variety of methods are used to push / insert the weft, including but not limited to shuttle looms, rapier fabrics (single rigid, dual rigid, dual flexible and dual telescopic), projectiles, air jets and water jets. In addition to the more traditional single weft insertion (or single weft insertion), multi-phase weft insertion (or weft insertion) is also used. For all these applications, one of the limiting factors of loom performance is the speed at which the weft can traverse the warp. This speed tends to be limited by many factors, including but not limited to the resistance and turbulence / stability experienced during the traversal process. These limitations can be greatly alleviated by synchronizing (or phasing or timing) energy deposition before any of the above-mentioned moving objects (shuttle looms, rapiers, projectiles, air jets, water jets) to reduce resistance, improve stability, and increase the speed at which the weft / weft yarn can traverse the warp. In particular, this energy deposition can take the form of obtaining a low-density tube or a series of low-density tubes to accelerate and guide the weft through the warp. This improved speed and stability can promote the faster throughput of any single or multi-phase weft / weft insertion method.In addition to improving the productivity of the loom by improving the throughput in terms of speed, the enhanced stability that can be achieved when propagating through the low-density tube also enables the weft to stably travel longer distances (this allows the loom to produce a larger final product with a wider width).In addition to saving costs in building a longer loom (it produces a finished braid with a larger width), the other benefit of the weft traveling a longer distance is that more wefts are arranged for each initial acceleration and final deceleration event, so the acceleration and deceleration time and energy are better utilized.Any of these improvements (higher speed or greater width) will improve the productivity of the loom, and their combination, with respect to producing a larger fabric area in a shorter time, can obtain a greater productivity increase.As a result, the phasing / synchronization / timing of energy deposition before any method for propagating the weft on the warp can increase loom output and cost-effectiveness.

[0228] When a tangible object such as a rapier, shuttle or projectile is used, the dynamics of energy deposition are very similar to those described for reducing drag on an aircraft or ground vehicle, as the energy line is deposited in front of the object, thereby minimizing its drag and increasing its stability. These same concepts also hold true when using air or water jets, and these concepts are described in more detail herein. Air and water jets are typically used when high throughput is required because there is no additional inertia other than the thread / filler / yarn itself. The additional inertia of the shuttle, rapier or projectile increases the time required for the warp thread to accelerate and decelerate, and causes additional unnecessary stress on the thread / filler / yarn itself. In the case of an air jet, a profiled reed can be used to provide a path for the propagation of the warp thread. An initial burst of air launches the warp thread, which is rapidly decelerated due to the effects of drag, and is subject to instability at higher speeds due to turbulence and drag, and its speed is therefore limited. (In the case of a water jet loom, the weft is propelled via jets of water rather than air, and the considerations we discussed for air jet looms apply equally to water jet looms.) The booster jets serve to reaccelerate the weft after it has slowed between booster jets, always keeping it below the maximum speed it can maintain in a standard atmosphere. One way to alleviate the problems caused by air drag is to propagate the weft through a vacuum, low pressure and / or high temperature environment. This technology has been developed for use in many industries (e.g., as a coating for Mylar films in the packaging industry, etc.). Another benefit of using energy deposition, as opposed to operating in a vacuum, low pressure and / or high temperature environment, is that the weft and the propulsion jets gain tremendous stability when propagating in this low-density tube, which is enhanced by the fact that the tube length and time scales can be well matched to the weft and its propagation. Since the warp threads must be free to swing back and forth, it is not possible to install a physical evacuated tube along which we can propel the weft with compressed air booster nozzles. In order to temporarily create a low-density tube in the air that can guide the warp threads and make them more easily propelled by a compressed gas booster, depositing energy provides the benefits of a rigid evacuated conduit without introducing physical obstacles that hinder the movement of the warp threads. When implementing our energy deposition method, most of the current design can remain unchanged. The booster will still propel the weft threads, and its support structure (such as a profiled reed) can also be used as a support structure for energy deposition, which will be composed of optical or high-voltage electrodes or some combination of the two, with each support structure containing a combination of them being much simpler than current high-voltage boosters. If only laser energy is used to deposit energy, only the optical elements need to be positioned on the booster support structure. If only discharge energy is used, only the high-voltage electrodes need to be positioned on the booster support structure. If both types of energy are used, both the optical elements and the high-voltage electrodes need to be mounted on the booster support structure.The fact that the weft threads are subject to much less wear and tear due to turbulence and drag, and the fact that they are better supported and face much less drag when propagating through the low-density tube, will enable the weft threads to propagate longer distances.

[0229] In one embodiment, matching the low density tube diameter to a 0.6 mm diameter thread requires the deposition of approximately 6 mJ of energy per 10 cm length. If the speed of the weft thread passing through the low density tube is significantly higher at 300 m / s, rather than the typical peak weft thread speeds ranging from 1200 m / min (~20 m / s) to 4800 m / min (~80 m / s), it travels 4 to 12 times faster than it would without relief. At this speed, the weft thread travels 4 to 15 times faster than it would without energy deposition. Moreover, if a loom can now be made that is 3 times longer (wider) due to the increased stability of the weft thread trajectory and the increased speed, the fabric produced per weft thread transfer is also 3 times larger. As a result, if both speed and width are increased according to this embodiment, the total loom output will be increased, in the range of 12 to 45 times, compared to the output of a loom that has not been improved by using energy deposition to facilitate the weft thread travel. If one considers the range of extended / improved / enhanced loom widths to be 2 to 4 times longer, then the improvement in loom output by depositing energy in front of the weft is an 8 to 60 times extension. For larger weft diameters, a larger diameter low density tube will be created to facilitate its propagation. Since the energy required varies in proportion to the volume of this low density tube it opens, the energy per unit length is proportional to the square of the tube diameter, which will be roughly proportional to the square of the weft diameter, since we tend to open tubes slightly larger in diameter than the weft diameter to minimize wear on the weft / fiber / material.

[0230] To provide additional confinement of ionic solutions in water jet applications or conductive fibers in air jet or water jet applications, a strong magnetic field may be aligned with the desired direction of propagation of the high speed wire to more accurately constrain the path of the conductive solution and / or wire.

[0231] Energy is deposited in the barrel of a gun, firearm or barrier breaker, and other types of barrels used to propel projectiles, so as to force the air in the barrel to flow out. The reduced drag on the projectile will enable a greater muzzle velocity to be achieved with the same drive energy (e.g., propellant in a conventional gun or electrical drive energy in a rail gun). The reduced drag will also allow a speed comparable to that achieved without modification to be achieved by using less drive energy. In a conventional gun, this means that the same performance can be achieved with less propellant. Then, when the projectile leaves the barrel, the lower propellant requirement results in a reduced muzzle blast. This reduced acoustic signature is useful for minimizing harmful effects on the hearing of nearby individuals, including one (or more) operators. This reduced acoustic signature can also weaken detection by acoustic means (similar to acoustic suppressors).

[0232] Energy deposition to force air out of the barrel can be applied in a variety of forms. For example, two embodiments are: i) electromagnetic energy deposition inside the barrel; or ii) it can be chemical in nature; and some combination of these two energy deposition methods. The electromagnetic energy can be, for example, in the form of a discharge inside the barrel. One embodiment that can achieve this is to ensure the separation of two electrodes that can discharge through a non-conductive gap; or a charged electrode discharges into a conductive barrel or other structural part that houses the barrel. Chemical energy can be, for example, in the form of an additional propellant that, when ignited, expands in front of the projectile to drive the gas from the barrel (as opposed to the traditional role of the propellant expanding behind the projectile to push it out of the barrel). This additional propellant can be incorporated into a bullet body, and one embodiment is to incorporate a conductive path in the bullet that conducts an electrical ignition pulse to ignite the propellant at the tip of the bullet. This path can be a fully internal closed circuit in the bullet. It can also be combined with a conductive support structure and / or barrel to close its circuit. One of the many embodiments for igniting a barrel clearing propellant is to incorporate a piezoelectric structure into the round to generate a high voltage when the round is struck by its usual firing mechanism. This high voltage can ignite the barrel clearing propellant at the tip of the round to clear the air in the barrel to promote better acceleration of the projectile or load of the round as the explosive used to accelerate it is propelled.

[0233] In either case, the total energy deposited in front of the round, by discharge, chemical propellant, or a combination of both, should be sufficient to significantly clear the air in the barrel before the load or projectile is accelerated away from the round. This energy should be sufficient to clear the volume of the barrel, so it should be 3*p o *The magnitude of V, where V is the barrel volume and p ois the ambient pressure. Assuming an ambient pressure of standard atmosphere, the energy required to clear the barrel of a 16" 12" shotgun is approximately 12J of energy. This is particularly useful for barrier breaker rounds, where the greater velocity of barrier breaker loads and reduced propellant requirements to minimize acoustic impact on personnel provide a significant benefit. The same calculation can be performed to clear the air in essentially any size barrel, simply calculating the energy requirement based on volume. This energy requirement can be increased in order to offset any cooling that the heated gases may experience as they travel down the barrel. In other words, a greater amount of energy can be deposited, containing 2, 3, 4, 5, or even up to 10 times the energy to accommodate different considerations, while still achieving the desired barrel clearing.

[0234] The apparatus for achieving this purpose may be constructed to achieve the above-mentioned power, including a barrel and / or supporting structure (e.g., a firearm, cannon, mortar, etc.) and any bullet, including but not limited to small caliber, medium caliber, and large caliber bullets, including conventional bullets and unconventional bullets, such as barrier breaker bullets.

[0235] In multiphase flow applications (including but not limited to powder coating and ultrasonic jet deposition applications), phasing of energy deposition using other processes (including but not limited to: powder explosion; spray explosion; explosion of different gases at different pressures; plasma explosion; application of heating; application of discharge; application of laser pulses; and others) can bring many benefits to the multiphase flow applications when the energy deposition is synchronized with such other processes compared to applications when the energy deposition is not synchronized with such other processes. In other forms of energy deposition, similar to other applications disclosed herein, discharges can be used to deposit the energy into the flow and open a low-density tube from the nozzle to the substrate, thereby more effectively guiding the particles toward the substrate at a higher speed. The discharge can be initiated / guided by a laser plasma such as a laser filament. The particle stream can also help to carry out the discharge; or a preferred conductive path can be used to guide the discharge along a line extending from the nozzle to the substrate. For small-scale applications, laser plasma / filaments can be used alone to open a small diameter low-density tube (commensurate with a small nozzle outlet).

[0236] In particular, the enhancement of ultrasonic spray deposition of various materials can be achieved by combining other pulse processes to deposit energy in order to achieve more effective impact speeds, and to obtain improved effects according to the desired results, such as coating quality, coating uniformity, surface wear, adhesion, crystallinity, coating strength, corrosion resistance, etc. When depositing this energy into an ultrasonic stream, we can also adjust the pressure and gas density to generate a more effective plasma for plasma deposition. It is also possible to adjust the flow temperature and density, thereby allowing higher particle speeds, because the pulse conditions allow these higher particle speeds to be subsonic at higher speeds in the sound environment we create. According to the geometry of the energy deposited, we can eliminate shock waves, which otherwise cause particles to separate within the flow, thereby producing a more uniform gas flow, particle distribution and deposition. The elimination and weakening of these shock waves also alleviates the deceleration generated for particles, thereby ensuring that the impact speed of particles on the substrate surface is higher and more uniform. If you want to adjust the radial particle distribution within the jet, you can place the energy along the center of the flow to push the particles outward to the edge of the flow. Alternatively, we can deposit energy at the edge of the fluid flow to push the particles toward the center of the fluid flow. By pulse-driving the gas feed of a multiphase material such as a powder, we can also synchronize the pulsed particle flow with the energy deposition. This allows us to create a low-density tube by depositing energy along the flow axis from the nozzle outlet to the substrate. The high speed of sound in this low-density tube enables the pulse of particles to propagate along the low-density tube at subsonic speeds, which would propagate at ultrasonic speeds if we did not deposit energy to create the low-density tube. In the case where the flow along the low-density tube is not completely subsonic, its Mach number is reduced, and due to the reduced Mach number we obtain, the negative effects of ultrasonic flow (such as impact shock structures at the substrate) are minimized. In addition to modifying and synchronizing the particle density distribution with energy deposition, we can also perform various forms of energy deposition simultaneously to affect the interaction of particles with the target surface. For example, in synchronization with the modulated particle distribution and the low-density tube formation, we can impinge one or more laser pulses, one or more discharges, modulated gas temperatures, and plasma and other modalities onto the target surface. There are many possible parameter ranges when performing this deposition, and their effects depend on the atmosphere, flow conditions, geometry, particles, feed rate, target material, and desired effects. As an example, we can synchronize the discharges in such a way that the low density tube they create is followed by a particle feed that fills the low density tube to achieve higher speeds. When the discharge is initiated, the particle feed begins (which can last for a few microseconds). The particle feed is released in bursts to synchronize with the creation and consumption of the low density tube. This timing and repetition rate depends on the flow conditions and geometry, while the discharge energy depends on the diameter of the spray nozzle and the distance from the substrate.In particular, as previously described, the magnitude of the discharge energy may be three times the product of the pressure inside the flow and the volume V determined by the cross-sectional area of ​​the spray nozzle outlet and the distance to the target surface (approximately 3*p. o *V). The repetition rate depends on the flow rate divided by the distance from the target surface, and the pulse period of the flow feed is less than or equal to the period during which the low-density tube can be filled and filled with multiphase flow, and then exhausted and form a stronger harmful impact structure on the substrate surface. In order to keep it less than the period during which the low-density tube can be filled with multiphase flow and then form an unfavorable impact structure, the multiphase flow can be synchronized / injected during 20%-95% of the period of propagation of the low-density tube. Its flow can also be slightly longer than the period of propagation of the low-density tube (for example 95-160% of this period) to allow time for the establishment of unfavorable impact structures on the substrate surface. When the impact structure begins to reform in the jet, the remaining particle flow can also help guide the discharge as the energy deposition source to the substrate as a ground. In principle, the energy deposition can also be used to regulate the particle flow, forcing it laterally away from the substrate into the decelerating high-density gas when the jet density begins to rise, and after the energy deposition creates the low-density tube, the particles are preferentially entrained in it and guided to the substrate at high speed. In such a geometry, we can ensure greater impact velocities, more uniform deposition, and better confinement of the flow into a low-density tube created by the deposited energy line. In addition to the particles we flow along this low-density tube, we can also use the corona of the high-voltage source we use for energy deposition; or use a radio frequency source to start a more efficient plasma at a lower density. Similarly, the stream of laser pulses or high repetition rate laser pulses can be synchronized with the particles impacting the target surface. These forms of additional energy can be injected into the process (e.g., plasma and laser, etc.) for all or part of the duration of the particle impacting the surface, and may include such additional energy injection before and / or after the particle impact to additionally treat / affect the surface before impact; and / or additionally treat / affect the particle after impact; and / or both, especially when the coating is formed. After the low-density tube and the modulated / synchronized particle flow are exhausted, this process can be repeated within a single cycle of the low-density tube.

[0237] This synchronization is effective for a wide range of particle sizes and material densities, as well as a wide range of flow conditions, resulting in a more flexible, capable and cost-effective high-speed spray process, such as coating, cleaning, shot peening, and other surface treatments. Particle density can range from 0.8 to 23 g / cc, drive pressure can range from 1 to 60 bar, unimpaired flow Mach number ranges from 1-12, where particle velocity ranges from 150-3000 m / s and the ratio of particle velocity, depending on various conditions, can be in the range of 0.1 to 1.0. Exemplary particles include but are not limited to abrasives, shot peening materials, dielectrics and metals. As a specific example, using a powder density ranging from 2-10 g / cc, and a flow Mach number from 2-5, where particle velocity ranges from 400-1200 m / s, the nozzle can have an outlet area A and be set at a distance L from the substrate (so that the area of ​​the spray column between the nozzle and the substrate is approximately equal to the product of A*L). The amount of energy required to open the low-density tube in the column is roughly equal to 3*A*L times the pressure in the column, which, depending on various conditions, can be higher than atmospheric pressure. In order to open the low-density tube of continuous flow, end-to-end will require the application of this energy at a repetition rate of gas flow velocity divided by distance L. A theoretical example can be a nozzle outlet area of ​​50 square mm, a distance L of 10 cm, and a theoretical pressure of ~2 bar, resulting in a roughly 1J energy requirement to open the tube. For a distance L of 1 cm, this energy will be reduced to 100mJ, however, the repetition rate will be adjusted to require the same power because the repetition rate is inversely proportional to L. The range of useful repetition rates can be 0.2-3 times the end-to-end repetition rate of a simply calculated gas velocity / L, more typically 0.8 to 1.6 times this simply calculated repetition rate. Similarly, the useful amount of energy deposited ranges from 0.2 to 3 times the simply calculated energy of 3*A*L times the pressure in the column (difficult to generalize as it varies within the column, and this value is best evaluated for each application, operating geometry, and set of conditions). The benefit of the additional power investment is improved coating and processing results, and the ability to achieve results that would not otherwise be possible. Since particle velocities can be increased and material processes are enhanced with the deposition of energy, the overall power requirements can be reduced via this energy deposition, with the payback rate increasing with increasing drive pressure and gas flow rate.

[0238] Depositing energy along the surface of a vehicle to open a low-density (high temperature) channel with high-speed sound has been disclosed in the past. Generally speaking, clearing the air under the vehicle will allow high-pressure explosion gases to escape faster, thereby reducing the residence time of high-pressure gases under the vehicle, and thereby minimizing the force and impulse of high-pressure gases transmitted to the vehicle. Similar considerations can be applied to any surface subjected to shock waves. In addition to this general concept and application, we have further disclosed that energy is deposited into the ground or other materials under the vehicle, where the explosion originally stayed and was confined. This energy deposition is used to destroy the confining soil / material, thereby allowing the explosives to be further gradually discharged and emptied more quickly from under the vehicle through the low-density, high-speed sound area under the vehicle, which is also emptied when energy is deposited in the soil or other material that confines the explosion. If the explosion gases are not released, they will very effectively transfer momentum to the covering material that confines them, which in turn very effectively transfers this momentum to the vehicle. As energy is deposited to puncture the covering material and release pressure beneath the covering material, not only do the high pressure gases vent and quickly evacuate through the low density, high velocity sound region beneath the vehicle (because the energy deposition in the soil also creates a blast wave through the air which effectively clears the gas beneath the vehicle), but the soil or covering material (which otherwise would have been more evenly accelerated into the vehicle) is now more distributed in a column around the puncture, and this column of material affects the vehicle more slowly than it would have otherwise been in an unmitigated condition. As a result, in both cases, namely, depositing energy under the vehicle to clean the gas under the vehicle (typically using an electrical discharge to pulse / suddenly heat the gas to generate a shock wave that drives ambient air out from under the vehicle) and depositing energy into the soil or cover material to confine the buried explosive / impact material under the vehicle so as to disrupt the soil or cover material and release the explosive gases (typically using electrical discharges, laser pulses, or a combination of both to deposit energy into the soil or cover material), the total momentum transferred from the impact material to the vehicle can be reduced by at least 30%, and the average acceleration experienced by the vehicle and its contents can be reduced by at least 70%. To clean or rarefy the gas under the vehicle, approximately 3*p o * The energy of V, where p o is the ambient atmospheric pressure beneath the vehicle, and V is the volume to be cleared / thinned beneath the vehicle. The amount of energy required to disrupt or puncture the soil or other cover material depends on the cover material and how much of it must be disrupted. Therefore, it is best to simply deposit an amount of energy that can be efficiently carried and deployed and that is neither too much nor too little for the vehicle. All of these considerations depend on the vehicle itself and how it is configured. This number can typically be on the order of 10kJ to 1MJ. Assume a chassis area of ​​~8m at the large end of this scale.2 , where the vehicle clearance is ~20cm, the energy required to clear the air is ~0.5MJ, leaving 0.5MJ to pierce / destroy the soil / cover material. Since most explosive devices have energy content up to hundreds of MJ with an input of 1MJ or less, in order to greatly reduce the resulting vehicle acceleration and eliminate over 30% of the total momentum on the vehicle, in the example of a 300MJ explosion, an input of <1MJ in the deposited energy can reduce the blast load on the vehicle by approximately 100MJ.

[0239] Fig.37 1 is a schematic diagram depicting an embodiment of an air jet weaving machine 1000 equipped with a directed energy deposition device 1016. The directed energy deposition device 1016 includes a pulsed laser subassembly 1014 configured to generate a straight path extending from a weft delivery nozzle 1004 to an opposing electrode 1018 and passing through a portion of a span defined by warp threads 1010A-B (forward and rearward positions) and the contour of a profiled reed 1008A-B attached to a sley 1012. In operation, at a predetermined time, the directed energy deposition device 1016 deposits electricity along the straight path to create a low-density guide path A. The nozzle 1004, which is in communication with a high-pressure air supply 1006, then pushes a portion of the weft threads 1002 through the low-density guide path A.

[0240] Fig.38 2 is a schematic diagram depicting an embodiment of a firearm subassembly 2000 having an integral directed energy deposition device 2002. In operation, the directed energy deposition device 2002 can be used to clean fluid in the bore of a barrel 2004, thereby creating a low density region A. While the low density region A persists, a projectile 2006 can be expelled through the barrel by igniting a propellant 2008. The energy deposition device 2002 can include, for example, a power source coupled to an insulated electrode exposed to the bore region of the barrel. In this method, energy deposition can include an electric arc. In other bore cleaning methods, the bore gas can be heated and expelled therefrom by igniting a chemical pre-propellant prior to igniting the propellant 2008.

[0241] Fig.41 is a schematic diagram depicting an embodiment of a vehicle 3000 equipped with an explosion mitigation device. The explosion mitigation device includes sensors 3002A-B and directed energy deposition devices 3008 positioned around a vehicle body 3004 and exposed to a vehicle chassis 3006. When sensors 3002A-B are triggered, energy deposition devices 3008 deposit energy along a path A into the space between chassis 3006 and the ground, thereby creating a low-density area B.

[0242] Fig.42is a schematic diagram depicting an embodiment of a vehicle equipped with a ground modification device 4000. The ground modification device includes sensors 4002A-B and directed energy deposition devices 4008 positioned about a vehicle body 4004 and exposed to a vehicle chassis 4006. When sensors 4002A-B are triggered, energy deposition devices 4008 deposit energy into the ground along a path A, resulting in at least penetrating a surface and causing a break or separation (e.g., a hole) B in the surface material.

[0243] Fig.43 is a schematic diagram depicting an embodiment of a directed energy deposition apparatus 5000 having a pulsed laser subassembly 5002. The pulsed laser subassembly 5002 includes a pulsed laser 5004 aligned with a beam splitter 5006, which in turn is aligned with a reflector 5008. In operation, the pulsed laser 5004 can generate a laser beam A, which can be split into two beams, and the two beams are delivered into a fluid outside the directed energy deposition apparatus 5000.

[0244] Fig.44 is a schematic diagram depicting an embodiment of a firearm cartridge 6000 having a directed energy deposition device 6002 integrated therein. The cartridge 6000 further includes a synchronization controller 6004 configured to synchronize the operation of the directed energy deposition device 6002 with the ignition of the propellant 6006. The synchronization controller 6004 may be configured to first trigger the operation of the directed energy deposition device 6002, and subsequently ignite the propellant 6006 and release the projectile 6008.

[0245] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. A method of improving the performance and capability of a firearm, gun or barrier destroyer by depositing energy in a barrel used to guide a projectile so as to force the air within the barrel out.

2. A method for forming a transmission path may include: a) emitting a first energy source to disrupt a standing wave of the fluid near the vehicle; b) passing a second energy source through the damaged portion of the fluid; This is followed by c) introducing a third energy source into the fluid to form the transmission path.

3. The method of claim 2, wherein: The first energy source may include a laser beam; the second energy source may include an electron beam; the third energy source may include a laser beam.

4. A method of reducing drag on a ground vehicle by synchronizing energy deposition with the motion of the vehicle and instantaneous suspension and propulsion forces, and the energy used to develop these forces.

5. A method of propelling a vehicle through the atmosphere, the method comprising: i) heating a portion of the atmosphere in front of and / or beside the vehicle to form a low density region comprising: a) forming an initiation zone in front of the vehicle, the initiation zone being configured to couple and absorb energy deposition; and b) depositing energy in the initiation region to form the low-density region; ii) guiding at least a portion of the object into the low-density region; and simultaneously iii) detonating the reactants in a pulsed propulsion unit that propels the vehicle.

6. The method of claim 5, wherein: The vehicle is a transport vehicle, a delivery vehicle, a cargo plane, an ultrasonic vehicle, a hypersonic vehicle or a high-altitude vehicle.

7. A method as claimed in claim 5, wherein when the vehicle includes ultrasonic and / or hypersonic propulsion, the energy deposition is phased relative to the detonation in the engine (e.g. a pulse detonation engine), which results in appropriate phasing of the fluid dynamic processes (the timing will depend on factors such as the length scale of the vehicle and one (or more) propulsion units, as well as flight conditions and parameters).

8. The method of claim 5, wherein the boost pulses may also be synchronized to generate the laser pulses and power to provide the pulsed power supply.

9. A ground vehicle transportation system comprising: i) a track assembly comprising: a) Tracks; b) Power supply; ii) a storage device configured to receive and store a portion of the power source; iii) a laser configured to generate at least one path connecting one or more electrodes present on the body of the ground vehicle and a portion of the track assembly, the portion of the track assembly being located forward of the vehicle; iv) a directed energy deposition device configured to deposit a portion of the stored power along the at least one path; and v) A controller configured to synchronize the receipt of the portion of the power, the generation of the at least one path, and the deposition of the portion of the stored power.

10. The method of claim 9, wherein: The ground vehicle is a train, a maglev train, a high-speed train, a bullet train or a hyperloop train.

11. A method of modifying a shock wave, blast wave and / or explosion gasses proximate at least a chassis of a vehicle in contact with an underlying surface and present in the fluid, the method comprising: i) heating a portion of the fluid along at least one path extending between the base pan and the lower surface to form at least one volume of heated fluid extending outwardly from the path; as well as ii) timing the heating to modify the shock wave.

12. The method of claim 11, wherein: The vehicle is a military vehicle, an armored vehicle, a Humvee, an armored personnel vehicle, a passenger car, a train and / or a minesweeper.

13. A method of ultrasonically depositing a spray onto a surface, the method comprising: i) directing at least one laser pulse through the fluid onto the surface to form at least one path through the fluid, the at least one path being between the ultrasonic nozzle and the surface; ii) releasing a certain amount of electrical energy along the path to form a low-density tube; iii) A few microseconds later, this is followed by the discharge of powder, granules and / or atomized material from the ultrasonic nozzle into the low-density tube.

14. A method of physical vapor deposition using a spray deposition apparatus or spraying.

15. A method as claimed in claim 14, which may include depositing metal powder onto the metal surface.

16. The method of claim 14, wherein the spraying techniques include, but are not limited to, thermal spraying, plasma spraying, detonation spraying, arc spraying, flame spraying, high velocity oxygen fuel spraying, warm spraying, cold spraying, and other spraying techniques under different operating atmospheres / conditions and media.

17. A method comprising the use of laser emission, comprising: i) One or more ground-based lasers as a propulsion source, firing at the rear end of the vehicle, with the propulsion lasers being refocused via rearward-facing optics to cause the gas or ablation product to heat and expand out of the rear end of the vehicle.

18. A method for phased energy deposition using pulsed power, comprising PDE / chemical laser / pulsed power (including: electric propulsion, and magnetic levitation).

19. A method of reducing base drag generated by a low pressure area near the rear of a vehicle, the method comprising: i) impulsively depositing energy along at least one path in front of the vehicle, whereby a volume of fluid is displaced from the at least one path; as well as ii) directing a portion of the displaced volume of fluid into the low pressure region, thereby increasing the pressure of the low pressure region.

20. The method of claim 19, further comprising propelling the vehicle by a pulsed propulsion unit, and synchronizing the discharge of the energy deposition device with the generation of propulsion pulses from the pulsed propulsion unit.

21. A method of reducing the wave drag exerted by a fluid against a forward cross-section of a fuselage, the fuselage including a plurality of inlet nozzles, the method comprising: i) pulse-heating a portion of the fluid to form a lower density region (e.g., aligned or substantially aligned with the longitudinal center axis of the fuselage) surrounded by the higher density region, the higher density region including at least part of the portion of the heated fluid; ii) directing a first portion of the fuselage into the lower density region, said first portion of the fuselage not including a plurality of fluid intake nozzles; as well as iii) simultaneously, directing a second portion of the fuselage into the higher density region, said second portion of the fuselage comprising at least one air intake nozzle.

22. A method of controlling discharge geometry and discharge time to produce significant benefits in various applications, including: Spraying conductive paths and / or patterns using laser pulses, and Energy is deposited through this conductive path.

23. The method of claim 22, wherein: The laser pulses are filamentation laser pulses.

24. A method of generating a low-density fluid region, comprising: i) an array of energy emitting elements arranged on the body, ii) Coordinating the emission of energy emitting elements to increase the effectiveness and / or amplitude of energy deposition.

25. The method of claim 24, wherein: The energy emitting element array includes a central core, an inner annular array and an outer annular array, both centered on the central core.

26. The method of claim 24, wherein: The energy emitting element is controllably emitting continuously.

Images