A field-reversed pulsed plasma thruster

Abstract

The present invention relates to a field-reversed configuration pulse plasma thruster, comprising: a spiral wave antenna, a preionization cavity, a main discharge cavity, a rotating magnetic field antenna group, a bias magnetic field coil group and a gas distributor. The cylindrical preionization cavity and the conical main discharge cavity are made of high-temperature resistant insulating materials. The spiral wave antenna is installed outside the preionization cavity, and preionizes the gas working medium under the excitation of radio frequency voltage. The rotating magnetic field antenna group is arranged outside the main discharge cavity, and generates a rotating magnetic field in the main discharge cavity under the drive of a high-frequency alternating current with a certain phase difference. The bias magnetic field coil group is used to generate an axial bias magnetic field in the preionization cavity and the main discharge cavity. The present invention uses spiral wave discharge to preionize the gas working medium, and ionizes and accelerates the plasma group through an angular rotating magnetic field and an axial bias magnetic field, so as to realize electrodeless electromagnetic acceleration, and at the same time has the advantages of high specific impulse, high efficiency, good power scalability, and diversified propellants.

Description

Technical Field

[0001] The present invention relates to the technical field of electric propulsion, and in particular to a field-reversed configuration pulsed plasma thruster. Background Art

[0002] Space exploration, power comes first. Deep space exploration missions such as Mars orbit and asteroid patrol are important components of my country's medium- and long-term space development strategy. Chemical propulsion is limited by the problem of low specific impulse (<1000s), and it is difficult to adapt to the mission requirements of deep space exploration; electric propulsion has the advantages of high specific impulse and high speed increment by ionizing and accelerating gas working fluid, and has become an important research field of advanced space propulsion. At present, the more mature Hall and ion thrusters have encountered problems such as increased electrode ablation and reduced economy when expanding to the power level of hundreds of kilowatts; variable specific impulse magnetoplasma rockets have problems such as complex multi-stage systems and large volume and weight; induction pulse plasma thrusters have problems such as high working voltage and large prototype size. Faced with the requirements of high specific impulse, high thrust, high power, and long life for the propulsion system put forward by deep space exploration missions, the existing electric thruster technology is difficult to fully meet and there are many technical problems. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a field-reversed configuration pulsed plasma thruster, which pre-ionizes the gas working medium through spiral wave discharge, and uses multiple groups of symmetrically arranged antennas to excite a rotating magnetic field in space, fully ionizes the gas working medium and forms a special field-reversed configuration plasma group, which is then ejected at high speed and obtains thrust. The thruster adopts an electrode-free structure as a whole, and there is no problem of electrode ablation.

[0004] A field-reversed configuration pulsed plasma thruster comprises: a helical wave antenna, a preionization chamber, a main discharge chamber, a rotating magnetic field antenna group, a bias magnetic field coil group and a gas distributor. The preionization chamber is connected to the main discharge chamber, the helical wave antenna is arranged outside the preionization chamber and is coaxial with the preionization chamber, the rotating magnetic field antenna group is arranged outside the main discharge chamber, the bias magnetic field coil group is arranged outside the helical wave antenna and the rotating magnetic field antenna group and is coaxial with the preionization chamber and the main discharge chamber, and the gas distributor is installed at the upstream central axis of the preionization chamber.

[0005] The spiral wave antenna is made of metal material with a special geometric shape, and the top and bottom branches are divided into two paths, so that the antenna consists of two separate halves. The spiral wave antenna is installed outside the pre-ionization chamber, and can induce spiral wave discharge of the gas working medium under the excitation of radio frequency voltage to pre-ionize the gas working medium.

[0006] The pre-ionization chamber is made of high temperature resistant insulating material and is a hollow cylinder with a diameter of 5 to 20 cm and a length of 5 to 30 cm. A circular hole is opened at the upstream axis of the pre-ionization chamber for introducing gaseous working medium, and the downstream is connected to the main discharge chamber.

[0007] The main discharge cavity is made of high temperature resistant insulating material, and the main body is a hollow cone with a small upstream diameter and a large downstream diameter. The cone angle is generally between 5° and 30°. The upstream of the main discharge cavity is connected to the downstream of the preionization cavity.

[0008] The rotating magnetic field antenna group includes a plurality of axial coils, which are uniformly distributed outside the main discharge cavity along the angular direction. Two opposite coils form a pair, with a total of n pairs, which are driven by high-frequency alternating currents with the same amplitude and frequency and a phase difference of m, and satisfy n×m=180°. Generally, the value of n is between 2 and 6.

[0009] The bias magnetic field coil group is composed of a plurality of coils arranged in sequence along the axis of the pre-ionization chamber and the main discharge chamber. In the pre-ionization chamber part, the coil diameter, number of turns and other parameters are the same, providing an axial bias magnetic field for spiral wave discharge; generally, the coil diameter is between 8 and 30 cm, and the number of turns is between 50 and 1000. In the main discharge chamber part, it gradually increases from upstream to downstream. Each coil is wound with enameled copper wire, and by adjusting the number of turns, current, position and other parameters, an axial bias magnetic field is provided for the acceleration of the field anti-configuration plasma group; generally, the coil diameter is between 10 and 50 cm, and the number of turns is between 50 and 1000.

[0010] The gas distributor is a "T"-shaped structure, made of insulating material, hollow inside, with multiple round holes on the side, and fixed to the round hole upstream of the pre-ionization chamber by a nut made of insulating material. The gaseous medium enters from the upstream of the gas distributor, is distributed through the round holes on the downstream side, and enters the pre-ionization chamber more evenly.

[0011] The working principle of the field-reversed configuration pulsed plasma thruster is as follows: when the thruster is working, the plasma group is ionized, confined and accelerated by the angular rotating magnetic field generated by the rotating magnetic field antenna group and the axial bias magnetic field generated by the bias magnetic field coil group. The gas working medium enters the pre-ionization cavity through the gas distributor and diffuses forward. Under the action of a certain power of radio frequency voltage, the spiral wave antenna excites a rapidly changing electromagnetic field in the internal space of the pre-ionization cavity, and then pre-ionizes the gas working medium and generates an initial plasma of a certain density. Under the action of a high-frequency alternating current with a certain phase difference, the rotating magnetic field antenna group generates an angularly rotating magnetic field inside the main discharge cavity, inducing electrons to move synchronously along the angular direction and quickly ionize the gas working medium. The high-intensity plasma current induces a closed magnetic flux structure in the opposite direction of the axial bias magnetic field generated by the bias magnetic field coil group, forming a field-reversed configuration plasma group, which is accelerated and ejected under the action of the Lorentz force and generates thrust. A single discharge process lasts about tens of microseconds.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention pre-ionizes the gas working fluid by means of spiral wave discharge, and can obtain a high-density initial plasma with high efficiency, which is beneficial to improving the process of driving the gas working fluid to form a field-reverse configuration plasma group by a rotating magnetic field, and improving the propulsion performance of the thruster.

[0014] 2. The present invention utilizes multiple pairs of antennas evenly distributed along the angular direction, and under the action of a high-frequency AC driving current with a certain phase difference, can generate an angularly rotating and evenly distributed magnetic field in the main discharge cavity. The rotating magnetic field can induce the ionization of the gas working medium and form a field-reversed plasma group. Under the action of the bias magnetic field, the field-reversed plasma group can obtain efficient acceleration and generate thrust.

[0015] 3. The field-reversed configuration pulsed plasma thruster proposed in the present invention adopts electrodeless discharge and does not have the electrode ablation problem inherent in Hall and ion thrusters. At the same time, it has the advantages of high specific impulse, high efficiency, good power scalability, diversified propellants, simple and compact structure, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an isometric view of a field-reversing pulsed plasma thruster in an embodiment of the present invention.

[0017] Figure 2a It is a front view of the field-reversed configuration pulsed plasma thruster in an embodiment of the present invention.

[0018] Figure 2b It is an axial cross-sectional view of a field-reversed pulsed plasma thruster in an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of a spiral wave antenna in an embodiment of the present invention.

[0020] Figure 4 Schematic diagram of a rotating magnetic field antenna in an embodiment of the present invention.

[0021] The numbers in the figure are explained as follows:

[0022] Helical wave antenna 1, pre-ionization cavity 2, main discharge cavity 3, rotating magnetic field antenna group 4, bias magnetic field coil group 5, gas distributor 6. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below in conjunction with embodiments.

[0024] like Figure 1 and Figure 2a and Figure 2b As shown, a field-reversed configuration pulsed plasma thruster according to an embodiment of the present invention includes: a helical wave antenna 1, a pre-ionization chamber 2, a main discharge chamber 3, a rotating magnetic field antenna group 4, a bias magnetic field coil group 5 and a gas distributor 6.

[0025] like Figure 3 As shown, the spiral wave antenna 1 is made of a copper tube with an outer diameter of 6 mm and an inner diameter of 4 mm, and the top and bottom branches are divided into two paths, so that the antenna is composed of two separate halves, and the diameter of the circular ring envelope at both ends is 100 mm. The spiral wave antenna 1 is installed outside the pre-ionization chamber 2, and can cause the gas working medium to generate spiral wave discharge under the excitation of the 13.56MHz radio frequency voltage, so that the gas working medium is pre-ionized.

[0026] The pre-ionization chamber 2 is made of quartz glass and is a hollow cylinder with an outer diameter of 86 mm, an inner diameter of 80 mm, and a length of 150 mm. A circular hole with a diameter of 14 mm is opened at the upstream axis of the pre-ionization chamber for installing a gas distributor 6, and is connected to the main discharge chamber 3 downstream.

[0027] The main discharge chamber 3 is made of quartz glass, and has a hollow cone body, a thickness of 3 mm, an upstream inner diameter of 80 mm, a downstream inner diameter of 200 mm, and an axial length of 230 mm. The upstream of the main discharge chamber 3 is connected to the downstream of the preionization chamber 2.

[0028] like Figure 4 As shown, the rotating magnetic field antenna group 4 includes 6 axial coils, which are made of copper tubes with an outer diameter of 6 mm and an inner diameter of 4 mm, and are evenly distributed outside the main discharge cavity along the angular direction. Two opposite coils form a pair, and there are 3 pairs in total. They are driven by high-frequency alternating currents with the same amplitude and frequency and a phase difference of 60°, respectively, to generate an angularly rotating magnetic field in the main discharge cavity 3.

[0029] The bias magnetic field coil group 5 is composed of 5 coils arranged in sequence along the axis of the pre-ionization chamber 2 and the main discharge chamber 3. In the pre-ionization chamber 2, the sizes of the two coils are both 164mm; in the main discharge chamber 3, the inner diameter of the coil gradually increases from upstream to downstream, which are 164mm, 232mm and 288mm respectively. The five coils are all wound with enameled copper wire with a wire diameter of 1mm, with 400 turns; from upstream to downstream, the distance between each other is 54mm. By adjusting the driving current of each coil, an axial bias magnetic field of 10-500Gs can be provided for the acceleration of spiral wave discharge and field anti-configuration plasma group.

[0030] The gas distributor 6 is a "T"-shaped structure, made of polytetrafluoroethylene, hollow inside, with 6 round holes on the side, and fixed to the round hole upstream of the pre-ionization chamber by an M14 polytetrafluoroethylene nut. The gaseous medium enters from the upstream of the gas distributor, is distributed through the round holes on the downstream side, and enters the pre-ionization chamber more evenly.

[0031] The working principle of the field-reversed configuration pulse plasma thruster is as follows: Xenon, argon, nitrogen and other types of gaseous working fluids enter the pre-ionization chamber 2 through the gas distributor 6 and diffuse forward. The spiral wave antenna 1 excites a rapidly changing electromagnetic field in the internal space of the pre-ionization chamber 2 under the action of a radio frequency voltage of 50W / 13.56MHz, thereby pre-ionizing the gaseous working fluid. The rotating magnetic field antenna group 4 generates an angularly rotating magnetic field inside the main discharge chamber 3 under the action of a high-frequency alternating current with a phase difference of 60°, a frequency of hundreds of kilohertz, and an amplitude of thousands of amperes, inducing electrons to move synchronously along the angular direction and quickly ionize the gaseous working fluid. The angular plasma current can reach tens of kiloamperes, which induces a closed magnetic flux structure in the opposite direction of the axial bias magnetic field generated by the bias magnetic field coil group 5, forming a field-reversed configuration plasma group, which is accelerated to tens of kilometers per second under the action of the Lorentz force, and a single discharge process lasts about tens of microseconds. At a repetitive operating frequency of several thousand hertz, tens to hundreds of millinewtons of thrust can be generated.

[0032] It should be understood that the above content is a further detailed description of the present invention in combination with a specific preferred embodiment, and it cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several simple deductions or substitutions, which should be regarded as belonging to the scope of patent protection determined by the submitted claims of the present invention.

Claims

1. A field-reversed pulsed plasma thruster, characterized in that: include: A spiral wave antenna, a preionization chamber, a main discharge chamber, a rotating magnetic field antenna group, a bias magnetic field coil group and a gas distributor; wherein the preionization chamber is connected to the main discharge chamber, the spiral wave antenna is arranged outside the preionization chamber and is coaxial with the preionization chamber, the rotating magnetic field antenna group is arranged outside the main discharge chamber, the bias magnetic field coil group is arranged outside the spiral wave antenna and the rotating magnetic field antenna group and is coaxial with the preionization chamber and the main discharge chamber, and the gas distributor is installed at the upstream central axis of the preionization chamber; The bias magnetic field coil group is composed of a plurality of coils arranged in sequence along the axis of the pre-ionization cavity and the main discharge cavity; in the pre-ionization cavity part, the coil diameter and the number of turns are the same, providing an axial bias magnetic field for the spiral wave discharge; the coil diameter is between 8 and 30 cm, and the number of turns is between 50 and 1000; In the main discharge cavity, the diameter gradually increases from upstream to downstream. Each coil is wound with enameled copper wire, and the axial bias magnetic field is provided for accelerating the field anti-configuration plasma group by adjusting the number of turns, current and position. The diameter of the coil is between 10 and 50 cm, and the number of turns is between 50 and 1000. The gas distributor is a "T"-shaped structure, made of insulating material, hollow inside, with multiple circular holes on the side, and fixed to the circular hole upstream of the pre-ionization chamber by a nut made of insulating material; the gas working medium enters from the upstream of the gas distributor, is distributed through the circular holes on the downstream side, and evenly enters the pre-ionization chamber; The spiral wave antenna is made of metal material, and the top and bottom branches are divided into two paths, so that the antenna consists of two separated halves; The spiral wave antenna is installed outside the pre-ionization chamber, and can induce spiral wave discharge in the gas working medium under the excitation of radio frequency voltage, so as to pre-ionize the gas working medium; The rotating magnetic field antenna group includes multiple axial coils, which are evenly distributed outside the main discharge cavity along the angular direction; two opposing coils form a pair, with a total of n pairs, which work under the drive of high-frequency alternating currents with the same amplitude and frequency and a phase difference of m, and satisfy n×m=180°; the value of n is between 2 and 6.

2. A field-reversed pulsed plasma thruster according to claim 1, characterized in that: The pre-ionization chamber is made of high temperature resistant insulating material and is a hollow cylinder with a diameter of 5 to 20 cm and a length of 5 to 30 cm. A circular hole is opened at the upstream axis of the pre-ionization chamber for introducing gaseous working medium, and the downstream is connected to the main discharge chamber.

3. A field-reversed pulsed plasma thruster according to claim 1, characterized in that: The main discharge cavity is made of high temperature resistant insulating material, and the main body is a hollow cone with a small upstream diameter and a large downstream diameter. The cone angle is between 5° and 30°. The upstream of the main discharge cavity is connected to the downstream of the preionization cavity.

4. A method for operating a field-reversed pulsed plasma thruster according to any one of claims 1 to 3, characterized in that: When the thruster is working, the plasma group is ionized, confined and accelerated by the angular rotating magnetic field generated by the rotating magnetic field antenna group and the axial bias magnetic field generated by the bias magnetic field coil group; the gas working medium enters the pre-ionization cavity through the gas distributor and diffuses forward, and the spiral wave antenna excites a rapidly changing electromagnetic field in the internal space of the pre-ionization cavity under the action of a certain power radio frequency voltage, thereby pre-ionizing the gas working medium and generating an initial plasma of a certain density; the rotating magnetic field antenna group generates an angularly rotating magnetic field inside the main discharge cavity under the action of a high-frequency alternating current with a certain phase difference, inducing electrons to move synchronously along the angular direction and quickly ionize the gas working medium, and the high-intensity plasma current induces a closed magnetic flux structure in the opposite direction to the axial bias magnetic field generated by the bias magnetic field coil group, forming a field-anticonfiguration plasma group, and the plasma group is accelerated and ejected under the action of the Lorentz force to generate thrust.

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