A dual-anode multi-modal micro-cathodic arc thruster and a method of operating the same

Abstract

The application belongs to the technical field of micro-arc thruster, and discloses a double-anode multi-mode micro-cathode arc thruster and a working method thereof; in the double-anode multi-mode micro-cathode arc thruster, the annular anode, the semiconductor trigger ring and the cathode ring are coaxially arranged, the semiconductor trigger ring and the cathode ring are installed on the larger diameter section of the stepped hole; the upper surface of the semiconductor trigger ring is in contact with the stepped surface of the stepped hole, the lower surface of the semiconductor trigger ring is in contact with the upper surface of the cathode ring, and the side surface of the semiconductor trigger ring and the side surface of the cathode ring are both provided with an insulating layer between the inner annular surface of the larger diameter section of the stepped hole; the umbrella handle is fixedly installed on the fourth through hole, and the umbrella surface faces the nozzle side; the cathode seat is fixedly installed on the larger diameter section of the stepped hole, so as to realize the fixed installation of the semiconductor trigger ring and the cathode ring. The application has the advantages of small volume, long service life and adjustable output parameter mode, and can complete the task of the micro-arc thruster.

Description

Technical Field

[0001] This invention belongs to the technical field of micro arc thrusters, and specifically relates to a dual-anode multi-mode micro cathode arc thruster and its working method. Background Technology

[0002] In existing technologies, traditional cold gas propulsion technology is difficult to meet the requirements of high efficiency and long service life, chemical propellants have potential risks such as explosion and toxicity, and the power system is difficult to miniaturize; in addition, there are many difficulties in miniaturizing high-power electric propulsion systems, and both technical principles and engineering processes face challenges.

[0003] The microcathode arc thruster is a new type of thruster with features such as simple structure, small size and mass, low power consumption, and high specific impulse. Explain, the principle of the microcathode arc thruster is that thrust is generated by ejecting highly ionized plasma produced by ablation of the cathode in a vacuum environment, and the specific impulse is improved by focusing it with an external magnetic field.

[0004] Existing micro-cathode arc thrusters only have a single operating mode, and their on-orbit operating parameters are uncontrollable. In addition, the thruster's lifespan is often limited by the unstable operation of the dynamic balance system of the conductive coating on the trigger system surface and the sputtering of metal droplets by the cathode spot. Furthermore, the design of some additional accelerating electrodes greatly increases the thruster's size, mass, and volume, making it difficult to meet the mission requirements of micro-arc thrusters, and it also suffers from the defect of limited operating mode adjustment range. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-anode multimodal microcathode arc thruster and its operating method to solve one or more of the aforementioned technical problems. The dual-anode multimodal microcathode arc thruster provided by this invention is a miniature plasma arc thruster with advantages such as small size, long lifespan, and adjustable output parameter modes, making it suitable for various applications requiring miniature arc thrusters.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a dual-anode multimodal microcathode arc thruster, comprising: an annular anode, a semiconductor trigger ring, a cathode ring, a cathode seat, and an umbrella-shaped anode;

[0008] The annular anode, the semiconductor trigger ring, and the cathode ring are all annular. The annular anode has a first circular through-hole at its center, which is a stepped hole, with the smaller diameter section of the stepped hole serving as a nozzle. The semiconductor trigger ring has a second circular through-hole at its center, the diameter of which is the same as the smaller diameter section of the stepped hole. The cathode ring has a third circular through-hole at its center, the diameter of which is smaller than the diameter of the second through-hole.

[0009] A fourth through hole is provided at the center of the cathode holder;

[0010] The umbrella-shaped anode includes an umbrella handle and an umbrella surface;

[0011] The annular anode, the semiconductor trigger ring, and the cathode ring are arranged coaxially. The semiconductor trigger ring and the cathode ring are installed in the larger diameter section of the stepped hole. The upper surface of the semiconductor trigger ring contacts the stepped surface of the stepped hole, and the lower surface of the semiconductor trigger ring contacts the upper surface of the cathode ring. An insulating layer is provided between the side surface of the semiconductor trigger ring, the side surface of the cathode ring, and the inner ring surface of the larger diameter section of the stepped hole. The umbrella handle is fixedly installed in the fourth through hole, and the umbrella surface faces the nozzle. The cathode seat is fixedly installed in the larger diameter section of the stepped hole to achieve the fixed installation of the semiconductor trigger ring and the cathode ring.

[0012] A further improvement of the present invention is that,

[0013] The distance between the bottom of the umbrella-shaped anode and the upper surface of the cathode ring is greater than the breakdown safety distance;

[0014] The contact area between the second through hole and the upper surface of the cathode ring is the cathode spot area, and the minimum distance from the cathode spot area to the umbrella surface is less than the maximum working distance for inducing discharge.

[0015] The diameter of the umbrella-shaped anode is smaller than the diameter of the second through hole but larger than the diameter of the third through hole. The plane containing the maximum radius of the umbrella-shaped anode is located between the plane containing the upper surface of the annular anode and the plane containing the upper surface of the cathode ring.

[0016] A further improvement of the present invention is that it further includes:

[0017] A chopper circuit, the two ends of which are respectively connected to the cathode ring and the handle of the umbrella-shaped anode via leads.

[0018] A further improvement of the present invention is that,

[0019] The fourth through hole is provided with a first internal thread;

[0020] The umbrella handle is provided with a first external thread that is adapted to the first internal thread;

[0021] The umbrella handle is adjustablely fixed in the fourth through hole via the first external thread and the first internal thread.

[0022] A further improvement of the present invention is that it further includes:

[0023] An excitation insulation support is provided, wherein the annular anode is nested and installed within the excitation insulation support;

[0024] The excitation insulation bracket has an excitation coil wound around its outer side. The excitation coil is used to provide a pulsed magnetic field under the action of an external excitation circuit. The operating frequency of the pulsed magnetic field is consistent with the ignition operating frequency of the dual-anode multimode microcathode arc thruster.

[0025] A further improvement of the present invention is that,

[0026] The insulating layer is made of polyimide or polyethylene insulating material;

[0027] The insulating layer is applied by coating or filling.

[0028] A further improvement of the present invention is that,

[0029] The inner ring surface of the semiconductor trigger ring is provided with a graphite coating.

[0030] A further improvement of the present invention is that,

[0031] The inclination angle of the umbrella-shaped anode is between 10° and 45°.

[0032] A further improvement of the present invention is that,

[0033] The cathode holder includes a base and a cylindrical protrusion; the protrusion is fixedly disposed at the center of the upper surface of the base, and the fourth through hole penetrates the base and the protrusion;

[0034] The protrusion is installed inside the third through hole; the protrusion extends out of the third through hole, and the extension height is greater than the breakdown safety distance.

[0035] This invention provides a method for operating a dual-anode multimodal microcathode arc thruster, comprising:

[0036] A trigger pulse voltage is applied between the annular anode and the cathode ring. Under the action of the semiconductor trigger ring, the irregular protrusions on the microscopic surface of the cathode ring generate electric field distortion. Under the action of the strong field, cathode electrons escape and bombard the anode and cause micro-explosion, generating a small amount of plasma and forming an arc discharge between the annular anode and the cathode ring.

[0037] The vacuum arc forms cathode spots on the cathode surface, ablates the cathode material, and emits more electrons and metal vapor. The ionized high-speed plasma is accelerated by the coupling of multiple physical fields such as thermal pressure, electric force, and electromagnetic force, and is ejected at high speed from the nozzle along the thruster axis, generating axial thrust.

[0038] The outward-diffused plasma provides a discharge channel between the umbrella-shaped anode and the cathode ring. Applying a trigger level to the umbrella-shaped anode induces a secondary discharge between the umbrella-shaped anode and the cathode ring, forming a larger amount of plasma.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The dual-anode multimode microcathode arc thruster provided by this invention is specifically a surface flashover triggered dual-anode multimode microcathode arc thruster. It adopts a dual-anode structure combining annular anodes and umbrella-shaped anodes. The voltage-adjustable umbrella-shaped anodes enhance vacuum arc discharge, improve cathode ablation rate and plasma jet ionization, and realize high-power mode propulsion. It is equipped with a semiconductor trigger ring, using semiconductor surface triggering technology to replace the traditional triggering method of ablation of the conductive film on the ceramic surface, avoiding ignition failure caused by the damage and consumption of the conductive film, and extending the service life of the thruster. Specifically, the inner ring surface of the smaller diameter segment of the annular anode and the upper surface of the cathode ring form the main trigger gap. The semiconductor trigger ring flashes along the inner ring surface of the second through hole, triggering cathode electron emission and generating a small amount of plasma, which induces discharge in the main trigger gap. After the main trigger gap discharge is formed, the umbrella anode in high-power mode attracts electrons with a high level, inducing secondary discharge in the umbrella anode and cathode spot. The secondary discharge trigger voltage is much lower than the flashover discharge trigger voltage of the annular anode and cathode ring along the surface material of the semiconductor trigger ring, which can provide a stable trigger level for the umbrella anode, avoid the use of large-mass energy storage capacitors and inductors, and greatly reduce the weight of the thruster itself.

[0041] In a preferred embodiment of the present invention, the continuous level of the umbrella-shaped anode can be changed by adjusting the duty cycle of the chopper boost circuit. A higher continuous level corresponds to a higher power output, thereby achieving stepless control of the thruster power and meeting the thrust requirements of micro-nano satellites for different missions during long-term on-orbit operation.

[0042] In a preferred embodiment of the present invention, the trigger electrode adopts a dual-anode structure, with the annular anode serving as the outer shell and mounted on an excitation insulation bracket, which can be used to wind the excitation coil. Further illustratively, the wound excitation coil, under the action of an external excitation circuit, provides a pulsed magnetic field. The operating frequency of the pulsed magnetic field is consistent with the thruster ignition frequency, which can constrain the plasma plume morphology of the thruster and improve the thruster's axial impulse.

[0043] In a preferred embodiment of the present invention, the umbrella-shaped anode is placed entirely in the central through hole of the annular anode, which can avoid the significant increase in overall volume caused by setting an accelerating anode outside the nozzle; in addition, the umbrella surface tilt angle is between 10° and 45°, and the anode umbrella surface is arranged along the plasma plume ejection trajectory, which on the one hand increases the contact area between the plasma plume and the umbrella-shaped anode, improving the success rate of secondary discharge, and on the other hand minimizes the loss of initial impulse caused by the direct collision of the plasma plume with the umbrella-shaped anode. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of a dual-anode multimode microcathode arc thruster in an embodiment of the present invention;

[0046] Figure 1 The reference numerals in the accompanying drawings are explained below.

[0047] 1. Annular anode; 2. Semiconductor trigger ring; 3. Cathode ring; 4. Cathode seat; 5. Umbrella-shaped anode; 6. Excitation insulation support. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0049] Please see Figure 1 In this embodiment of the invention, a dual-anode multimodal microcathode arc thruster is provided, comprising: annular anode 1, semiconductor trigger ring 2, cathode ring 3, cathode seat 4, and umbrella anode 5;

[0050] The annular anode 1, the semiconductor trigger ring 2, and the cathode ring 3 are all annular. The annular anode 1 has a circular first through-hole at its center, which is a stepped hole, with the smaller diameter section of the stepped hole serving as a nozzle. The semiconductor trigger ring 2 has a circular second through-hole at its center, the diameter of which is the same as the smaller diameter section of the stepped hole. The cathode ring 3 has a circular third through-hole at its center, the diameter of which is smaller than the diameter of the second through-hole.

[0051] The cathode seat 4 has a fourth through hole at its center; in an optional embodiment, the cathode seat 4 includes a base and a cylindrical protrusion, the protrusion is fixedly disposed at the center of the upper surface of the base, and the fourth through hole penetrates the base and the protrusion.

[0052] The umbrella-shaped anode 5 includes an umbrella handle and an umbrella surface. The diameter of the umbrella surface is smaller than the diameter of the smaller diameter segment in the stepped hole. In a preferred embodiment, the umbrella handle of the umbrella-shaped anode 5 is connected to a lead wire, which is connected to the lead wire of the cathode ring 3 in the same chopper circuit, which can more conveniently realize multi-mode adjustment.

[0053] During installation, the umbrella handle is fixedly installed in the fourth through hole, and the umbrella surface faces the nozzle side; the protrusion is adapted to be installed in the third through hole, and the protrusion extends out of the third through hole to support the umbrella surface and ensure a safe penetration distance; the annular anode 1 is installed on an external insulating bracket; the annular anode 1, the semiconductor trigger ring 2, and the cathode ring 3 are arranged coaxially, the upper surface of the semiconductor trigger ring 2 contacts the stepped surface of the stepped hole, the lower surface of the semiconductor trigger ring 2 contacts the upper surface of the cathode ring 3, and an insulating layer is provided between the side surface of the semiconductor trigger ring 2, the side surface of the cathode ring 3, and the inner wall of the larger diameter section of the stepped hole; the upper surface of the base contacts the lower surface of the cathode ring 3, and the cathode seat 4 is fixedly installed in the larger diameter section of the stepped hole to achieve the installation and fixation of the semiconductor trigger ring 2 and the cathode ring 3.

[0054] The technical solution provided in this invention adopts a dual-anode structure combining annular and umbrella-shaped anodes. The voltage-adjustable umbrella-shaped anode enhances vacuum arc discharge, improves cathode ablation rate and plasma jet ionization, and achieves high-power propulsion. A semiconductor trigger ring is provided, and semiconductor surface triggering technology is used to replace the traditional triggering method of ablation of the conductive film on the ceramic surface, avoiding ignition failure caused by the damage and consumption of the conductive film and extending the service life of the thruster.

[0055] Further explanation: The inner ring surface of the smaller diameter segment of the annular anode and the upper surface of the cathode ring form the main trigger gap. The semiconductor trigger ring flashes along the inner wall of its through-hole, triggering cathode electron emission and generating a small amount of plasma, which induces discharge in the main trigger gap. After the main trigger gap discharge is formed, the umbrella anode in high-power mode attracts electrons with a high level, inducing secondary discharge in the umbrella anode and cathode spot. The secondary discharge trigger voltage is much lower than the flashover discharge trigger voltage of the annular anode and cathode ring along the surface material of the semiconductor trigger ring. This voltage can be boosted by the onboard DC power supply through a chopper circuit, thus providing a stable trigger level for the umbrella anode. This avoids the use of large-mass energy storage capacitors and inductors, greatly reducing the weight of the thruster itself. By adjusting the duty cycle of the chopper circuit, the continuous level of the umbrella anode can be changed. A higher continuous level corresponds to a higher power output, achieving stepless control of the thruster power, thereby meeting the thrust requirements of micro-nano satellites for different missions during long-term on-orbit operation.

[0056] In a further preferred embodiment of the present invention, the fourth through hole is provided with a first internal thread, and the umbrella handle is provided with a first external thread adapted to the first internal thread. The umbrella handle is adjustablely fixed in the fourth through hole via the first external thread and the first internal thread. Explained, through this preferred connection method, different plasma plume morphologies are generated under different working environments (pulsed magnetic field), and a suitable working distance for inducing secondary discharge can always be found. This allows more positive ions to pass through the area surrounding the umbrella-shaped anode while ensuring successful discharge, reducing the initial impulse loss caused by positive ion bombardment of the anode. When positive ions move to the space region on the upper surface of the umbrella-shaped anode, the additional electric field of the umbrella-shaped anode can provide them with additional electric field acceleration. Therefore, the technical means of the present invention facilitates the adjustment of the preferred distance for inducing secondary discharge.

[0057] In a further preferred embodiment of the present invention, the height of the protrusion extending through the third through hole is greater than the breakdown safety distance, the distance between the bottom surface of the umbrella surface and the upper surface of the cathode ring is on the order of millimeters, and the minimum distance from the cathode spot area (the contact area between the second through hole and the upper surface of the cathode ring) to the umbrella surface is less than the maximum working distance for inducing discharge.

[0058] A further preferred embodiment of the present invention includes:

[0059] The excitation insulation bracket 6 is used to house the annular anode 1.

[0060] Explained, the trigger electrode employs a dual-anode structure, with the annular anode serving as the outer shell, secured to an external insulating bracket via external threads. This insulating bracket can be used to wind the excitation coil. Further explained, the excitation insulating bracket can be made of polyetheretherketone (PEEK) material, capable of winding the excitation coil and providing a pulsed magnetic field under the action of an external excitation circuit. The pulsed magnetic field operates at the same frequency as the thruster's ignition frequency, enabling constraint on the thruster's plasma plume morphology and improving the thruster's axial impulse.

[0061] In an exemplary optional embodiment, the outer ring surface of the annular anode 1 is provided with an external thread for connection to an external mounting bracket or excitation insulation bracket 6, thereby achieving the installation and fixation of the annular anode 1; the inner ring surface of the annular anode 1, on the side away from the nozzle, is provided with an internal thread for connection to the cathode seat 4, thereby achieving the installation and fixation of the cathode seat 4, cathode ring 3, and semiconductor trigger ring 2. The end of the cathode seat 4 away from the nozzle of the annular anode 1 is provided with an external thread for tight connection with the internal thread of the annular anode 1.

[0062] In an exemplary alternative, the insulating layer may be made of polyimide or polyethylene insulating material, and may be implemented in the form of coating or filling.

[0063] In a further specific and exemplary application scheme, the cathode seat has an arc-shaped keyway at the end away from the nozzle, and the cathode lead is led out from the keyway. The annular anode has an annular anode lead on its lower surface away from the nozzle. The cathode lead and the annular anode lead are used to connect to the two ends of the power processing unit circuit. Explained, the power processing unit converts the DC power output into pulse power release through inductor-capacitor energy storage elements, generating instantaneous high voltage to break down the thruster gap and realize thruster ignition.

[0064] In a further preferred embodiment of the present invention, the diameter of the umbrella-shaped anode surface is smaller than the inner diameter of the through hole of the semiconductor trigger ring and larger than the outer diameter of the through hole of the cathode ring; in addition, the plane containing the maximum radius of the umbrella surface is located between the plane containing the upper surface of the annular anode and the plane containing the upper surface of the cathode ring.

[0065] In this embodiment of the invention, the semiconductor trigger ring is made of silicon carbide semiconductor with graphite coating and other semiconductive coating composite materials. Explained, the semiconductor surface flashover triggering technology is used to replace the traditional conductive thin film ablation triggering technology. The consistency of the material interior is used to avoid the thin film breaking after repeated triggering, which would lead to ignition failure and greatly improve the service life of the thruster.

[0066] In a specific embodiment of the present invention, the working distance for inducing secondary discharge between the edge of the umbrella-shaped anode and the cathode spot is within 5 mm; the outer diameters of the annular anode, semiconductor trigger ring, and cathode ring are approximately on the order of centimeters. The outer surface contact surfaces of the semiconductor trigger ring and cathode ring are insulated with polyimide, and the inner surface of the semiconductor trigger ring is coated with graphite powder to further induce flashover along the inner surface of the semiconductor.

[0067] In a specific embodiment of the present invention, the annular anode has a stepped through-hole inside. The smaller stepped hole is located near the head of the thruster, with a diameter of approximately 13-15 mm and a step height of approximately 2-3 mm. The stepped surface is used to install the semiconductor trigger ring and the cathode ring. The larger stepped hole is located on the side away from the head of the thruster, with a diameter of approximately 17-18 mm and a step height of approximately 20-30 mm. It is machined with internal threads for engagement with the cathode seat. The cathode seat has three stepped surfaces, with a central threaded hole penetrating the cathode seat and machined with internal threads for installing the handle of the umbrella-shaped anode. The upper surface of the protrusion of the cathode seat is higher than the cathode ring, and the side of the protrusion is tightly fitted with the inner surface of the cathode ring, limiting the radial displacement of the cathode ring. The cathode seat may have a millimeter-radius arc-shaped groove drilled on the widest stepped surface to provide a routing channel for the bottom lead wire of the cathode ring.

[0068] In the technical solution provided by this invention, the umbrella-shaped anode is placed entirely in the central through hole of the annular anode, avoiding a significant increase in overall volume caused by setting an accelerating anode outside the nozzle; the umbrella surface tilt angle is between 10° and 45°, and the anode umbrella surface is arranged along the plasma plume ejection trajectory, which on the one hand increases the contact area between the plasma plume and the umbrella-shaped anode, improving the success rate of secondary discharge, and on the other hand minimizes the loss of impulse caused by the direct collision of the plasma plume with the umbrella-shaped anode; the handle of the umbrella-shaped anode penetrates the cathode seat; the vertical distance from the bottom of the umbrella surface of the umbrella-shaped anode to the cathode ring is on the order of millimeters and does not exceed the upper surface of the annular anode.

[0069] In this embodiment of the invention, the dual-anode circuit structure shares a common cathode; the anode ring circuit operates in a discontinuous pulse state with a frequency on the order of Hertz and a voltage duration on the order of microseconds; the umbrella-shaped anode circuit operates in a continuous circuit state with a stable and continuous voltage on the order of tens of volts.

[0070] In a specific embodiment of the present invention, a dual-anode multimode microcathode arc thruster is provided, comprising:

[0071] Annular anode 1;

[0072] Semiconductor trigger ring 2, the upper surface of which is in close contact with the lower edge of the first-stage stepped hole of the annular anode 1;

[0073] A cathode ring 3 is installed inside the annular anode 1, with its upper surface in close contact with the lower surface of the semiconductor trigger ring 2, and the side surface of the cathode ring 3 is insulated.

[0074] Cathode seat 4 is installed inside the annular anode 1. The central stud of the cathode seat 4 is inserted into the inner hole of the cathode ring 3. The bottom of the cathode seat 4 has an arc-shaped groove to lead out the wiring of the cathode ring 3. The side of the cathode seat 4 has an external thread that meshes with the internal thread of the annular anode 1.

[0075] The umbrella-shaped anode 5 is installed at the center of the thruster assembly. The umbrella surface of the umbrella-shaped anode 5 is made of titanium, and the handle is an M5 iron screw, which is fixed to the central stud of the cathode seat 4.

[0076] The excitation insulation bracket 6 is installed on the outermost layer of the thruster and is fixed to the external thread of the annular anode 1 by the internal thread. The outer side of the excitation insulation bracket 6 is used to wind the excitation coil.

[0077] In this embodiment of the invention, the semiconductor trigger ring is made of silicon carbide semiconductor and other semiconducting coating composite materials. Graphite is sprayed on the inner surface of the ring to reduce the surface flashover resistance, inducing flashover between the annular anode and cathode along the inner surface of the semiconductor trigger ring, generating a large amount of plasma within the thruster cavity. This plasma provides a discharge channel between the umbrella-shaped anode and cathode, inducing secondary discharge between the umbrella-shaped anode and cathode at a lower voltage, generating an even larger amount of plasma. The large amount of plasma generated by the dual-anode discharge increases the internal pressure of the cavity, causing the plasma to move towards the nozzle under the action of the pressure gradient and eventually be ejected outward to generate reverse thrust. A cathode lead is led out from the lower surface of the cathode seat. The annular anode has an M3 blind hole drilled on the side away from the nozzle for leading out the anode lead. The cathode lead and the anode lead are connected to a power processing unit. A gas discharge tube is connected in series between the anode lead and the energy storage element of the power processing unit to ensure that the voltage applied between the annular anode and cathode ring reaches a certain high voltage value, achieving stable triggering. Compared with other switching devices such as relays, the use of a gas discharge tube can further effectively reduce the thruster mass and size.

[0078] In this embodiment of the invention, a surface flashover-triggered dual-anode multimode microcathode arc thruster is provided, the working principle of which is as follows:

[0079] The working process can be roughly divided into three stages according to the time sequence: arc generation, plasma formation and acceleration, and plasma ejection. First, a trigger pulse voltage of several hundred volts is applied between the annular anode 1 and the cathode ring 3. At the same time, under the action of the graphite coating and the semiconductor trigger ring 2, the irregular protrusions on the microscopic surface of the cathode ring 3 generate electric field distortion. Under the action of the strong field, cathode electrons escape and bombard the anode, causing micro-explosions, generating a small amount of plasma, and forming an arc discharge between the annular anode 1 and the cathode ring 3. Then, the vacuum arc forms cathode spots on the cathode surface, ablates the cathode material, and emits more electrons and metal vapor. Finally, the ionized high-speed plasma is accelerated under the coupling effect of multiple physical fields such as thermal pressure, electric field force, and electromagnetic force, and is ejected at high speed along the thruster axis, generating axial thrust. The outwardly diffused plasma provides a discharge channel between the umbrella anode 5 and the cathode ring 3. A trigger level is applied to the umbrella anode 5 to induce a secondary discharge between the umbrella anode 5 and the cathode ring 3, forming a larger amount of plasma.

[0080] Further preferably, the plasma working fluid is accelerated by the Lorentz force generated by the coupling between the internal current generated by the plasma motion and the radial component of the external magnetic field to obtain a higher ejection velocity; the strength of the plume confinement magnetic field is adjusted by adjusting the number of turns and the current of the magnetic field coil, thereby adjusting the shape of the plasma ejection plume; different propulsion effects can be produced by adjusting the duty cycle of the chopper circuit to boost the output of different umbrella-shaped anode voltages and adjusting the magnitude of the discharge arc and the acceleration electric field.

[0081] In summary, the technical solution provided by this invention adopts a dual-anode structure combining annular and umbrella-shaped anodes. The voltage-adjustable umbrella-shaped anode enhances vacuum arc discharge, improves cathode ablation rate and plasma jet ionization, and achieves high-power propulsion. The use of silicon carbide composite semiconductor surface triggering technology replaces the traditional triggering method of ablation of the conductive film on the ceramic surface, avoiding ignition failure due to the damage and consumption of the conductive film, and extending the service life of the thruster.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A dual-anode multimode microcathode arc thruster, characterized in that, include: Annular anode (1), semiconductor trigger ring (2), cathode ring (3), cathode seat (4) and umbrella anode (5); The annular anode (1), the semiconductor trigger ring (2), and the cathode ring (3) are all annular; the annular anode (1) has a circular first through hole at its center, which is a stepped hole, and the smaller diameter section of the stepped hole is used as a nozzle; the semiconductor trigger ring (2) has a circular second through hole at its center, and the diameter of the second through hole is the same as the diameter of the smaller diameter section of the stepped hole; the cathode ring (3) has a circular third through hole at its center, and the diameter of the third through hole is smaller than the diameter of the second through hole; The cathode holder (4) has a fourth through hole at its center; The umbrella-shaped anode (5) includes an umbrella handle and an umbrella surface; The annular anode (1), the semiconductor trigger ring (2), and the cathode ring (3) are arranged coaxially. The semiconductor trigger ring (2) and the cathode ring (3) are installed in the larger diameter section of the stepped hole. The upper surface of the semiconductor trigger ring (2) is in contact with the stepped surface of the stepped hole, and the lower surface of the semiconductor trigger ring (2) is in contact with the upper surface of the cathode ring (3). An insulating layer is provided between the side surface of the semiconductor trigger ring (2), the side surface of the cathode ring (3), and the inner ring surface of the larger diameter section of the stepped hole. The umbrella handle is fixedly installed in the fourth through hole, and the umbrella surface faces the nozzle. The cathode seat (4) is fixedly installed in the larger diameter section of the stepped hole to achieve the fixed installation of the semiconductor trigger ring (2) and the cathode ring (3). The distance between the bottom of the umbrella-shaped anode (5) and the upper surface of the cathode ring (3) is greater than the breakdown safety distance; the contact area between the second through hole and the upper surface of the cathode ring (3) is the cathode spot area, and the minimum distance from the cathode spot area to the umbrella surface is less than the maximum working distance for inducing discharge; the diameter of the umbrella-shaped anode (5) is smaller than the diameter of the second through hole and larger than the diameter of the third through hole, and the plane containing the maximum radius of the umbrella surface is located between the plane containing the upper surface of the annular anode (1) and the plane containing the upper surface of the cathode ring (3).

2. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, Also includes: The chopper circuit has its two ends connected to the cathode ring (3) and the umbrella handle of the umbrella anode (5) respectively via leads.

3. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, The fourth through hole is provided with a first internal thread; The umbrella handle is provided with a first external thread that is adapted to the first internal thread; The umbrella handle is adjustablely fixed in the fourth through hole via the first external thread and the first internal thread.

4. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, Also includes: The excitation insulation bracket (6) is in which the annular anode (1) is nested and installed; The excitation insulation bracket (6) has an excitation coil wound around its outer side. The excitation coil is used to provide a pulsed magnetic field under the action of an external excitation circuit. The working frequency of the pulsed magnetic field is consistent with the ignition working frequency of the dual-anode multimode microcathode arc thruster.

5. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, The insulating layer is made of polyimide or polyethylene insulating material; The insulating layer is applied by coating or filling.

6. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, The inner ring surface of the semiconductor trigger ring (2) is provided with a graphite coating.

7. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, The inclination angle of the umbrella-shaped anode (5) is between 10° and 45°.

8. The dual-anode multimode microcathode arc thruster according to claim 1, characterized in that, The cathode seat (4) includes a base and a cylindrical protrusion; the protrusion is fixedly disposed at the center of the upper surface of the base, and the fourth through hole penetrates the base and the protrusion; The protrusion is installed inside the third through hole; the protrusion extends out of the third through hole, and the extension height is greater than the breakdown safety distance.

9. A method for operating the dual-anode multimodal microcathode arc thruster according to claim 1, characterized in that, include: A trigger pulse voltage is applied between the annular anode (1) and the cathode ring (3); Under the action of the semiconductor trigger ring (2), the irregular protrusions on the microscopic surface of the cathode ring (3) generate electric field distortion. Under the action of the strong field, cathode electrons escape and bombard the anode and cause micro-explosion, generating a small amount of plasma and forming an arc discharge between the annular anode (1) and the cathode ring (3). The vacuum arc forms cathode spots on the cathode surface, ablates the cathode material, and emits more electrons and metal vapor. The ionized high-speed plasma is accelerated by the coupling of multiple physical fields such as thermal pressure, electric force, and electromagnetic force, and is ejected at high speed from the nozzle along the thruster axis, generating axial thrust. The outward diffusion of plasma provides a discharge channel between the umbrella anode (5) and the cathode ring (3), applies a trigger level to the umbrella anode (5), induces a secondary discharge between the umbrella anode (5) and the cathode ring (3), and forms a larger amount of plasma.

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