Annular porous structure cathode for magnetic plasma power thruster
By designing a ring-shaped porous cathode and optimizing the inner and outer ring discharge cavities and gas supply holes, the problems of cathode burn-out and insufficient electron emission were solved, achieving efficient electron emission and heat removal, and improving the stability and lifespan of the magnetic plasma thruster.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF CONTROL ENG
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-12
AI Technical Summary
The cathodes of existing magneto-plasma-powered thrusters are prone to burn-out under high-power operating conditions, and the electron emission area is insufficient, affecting the thruster's lifespan and ignition stability.
A ring-shaped porous cathode is designed, comprising an inner ring emitter and an outer ring emitter, with a ring-shaped discharge cavity formed between the inner and outer rings. It is equipped with inner and outer gas supply holes and a tail gas cavity. The propellant is evenly distributed using a gas damping pad, and the discharge cavity depth is optimized to improve the electron emission area and heat removal efficiency.
It increases the effective current emission area of the cathode by more than 20%, reduces the phenomenon of uneven burning, ensures uniform distribution of propellant, and improves ignition stability and heat removal efficiency.
Smart Images
Figure CN122014551A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of electric propulsion power devices for spacecraft, and specifically relates to an annular porous cathode structure for a magnetic plasma propulsion thruster. Background Technology
[0002] With the development of electric propulsion platforms for spacecraft, various electric propulsion technologies have been researched and significant progress has been made. However, high-power space power technology is still in the research and development stage.
[0003] MPDT (Multi-Purpose Dynamic Thruster) is a type of electric thruster that converts electrical energy into the internal energy of a neutral gas, and then into directional kinetic energy. Compared to other types of electric thrusters, MPDT's advantage lies in its ability to simultaneously achieve high specific impulse and high thrust. The typical operating current of an MPDT is usually in the hundreds of amperes. As the electron emission source, the cathode needs to bear the electron emission of the entire thruster; the cathode of an MPDT operates in an extremely harsh environment, which is a bottleneck to the thruster's lifespan. Summary of the Invention
[0004] The purpose of this invention is to provide an annular porous cathode structure for a magnetic plasma propulsion thruster. Through the structural design of the inner and outer ring emitters, the effective current emission area of the cathode is increased by more than 20%, which ensures timely heat dissipation, reduces the occurrence of cathode burn-out, and improves ignition stability.
[0005] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions: A ring-shaped porous cathode for a magnetic plasma propulsion thruster is characterized by comprising a cathode body, the cathode body including an inner ring emitter and an outer ring emitter, the outer ring emitter being a cylinder with a circular groove at one end, the inner ring emitter being annular and disposed within the circular groove, the circular groove having a through hole, the internal through hole of the inner ring emitter being connected to the through hole to form an internal air supply hole, an annular discharge cavity being formed between the outer surface of the inner ring emitter and the side wall of the circular groove of the outer ring emitter, the annular discharge cavity and the internal air supply hole together constituting a cathode discharge channel; The circular groove is provided with multiple external air supply holes, and the other end of the outer ring emitter is provided with a tail air cavity, which is connected to the internal air supply hole and the external air supply hole.
[0006] A gas damping pad is provided inside the tail gas chamber to dampen the propellant flowing into one end of the tail gas chamber and to balance the distribution of propellant between the inner and outer gas supply holes.
[0007] The central axes of the inner ring emitter and the outer ring emitter coincide.
[0008] The depth of the annular discharge cavity is 30%-45% of the total length of the cathode body.
[0009] The ratio of the sidewall area of the inner air supply port to the total sidewall area of the multiple outer air supply ports is equal to the ratio of the inner ring sidewall area of the inner ring emitter to the sum of the inner ring sidewall areas and the outer ring sidewall areas of the outer ring emitter.
[0010] The outer diameter of the cathode body is 12~20mm, and the cathode body material is tantalum-tungsten.
[0011] It includes 7 external air supply holes, which are evenly distributed circumferentially.
[0012] The tail gas cavity has a circular cross-section, and the outer circular surface of the tail gas cavity is parallel to the outer circular surface of the annular discharge cavity.
[0013] The inner and outer walls of both the inner and outer ring emitters serve as electron emission surfaces.
[0014] The external air supply holes are tangent to the side wall of the circular groove of the outer ring emitter and the outer wall of the inner ring emitter, respectively.
[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The cathode structure designed in this invention can increase the effective current emission area of the cathode by more than 20%, while the homogeneous surface reduces the occurrence of cathode burn-out phenomenon.
[0016] (2) The preferred coaxial porous annular discharge cavity design of the present invention optimizes the ratio of depth to the entire cathode length, ensuring that the heat deposited during the cathode operation is timely and uniformly discharged along the porous structure.
[0017] (3) In the preferred embodiment of the present invention, the ratio of the area of the inner air supply hole to the area of the seven outer air supply holes is equal to the ratio of the surface area of the inner ring emitter and the outer ring emitter. This can ensure that the propellant density near the inner and outer emitters is uniform, ensure that the ionization rate of each region of the cathode is consistent, and improve ignition stability.
[0018] (4) In the preferred embodiment of the present invention, a gas damping pad is installed inside the tail gas cavity to dampen the propellant flowing from the left end, so as to ensure that the propellant can be evenly distributed between the inner and outer gas supply holes and reduce local ablation hot spots. Attached Figure Description
[0019] Figure 1 This is a front view of the annular porous cathode structure used in the magnetic plasma propulsion thruster of the present invention; Figure 2 This is a rear view of the annular porous cathode structure used in the magnetic plasma propulsion thruster of the present invention; Figure 3This is a side cross-sectional view of the annular porous cathode structure used in the magnetic plasma propulsion thruster of the present invention. Detailed Implementation
[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: like Figures 1-3 As shown, a ring-shaped porous cathode for a magnetic plasma thruster includes a cathode body 7, which includes an inner ring emitter 2 and an outer ring emitter 1. The outer ring emitter 1 is cylindrical with a circular groove at one end. The inner ring emitter 2 is annular and is disposed within the circular groove. A through hole is provided on the circular groove. The through hole inside the inner ring emitter 2 is connected to the through hole to form an inner air supply hole 3. An annular discharge cavity 8 is formed between the outer side of the inner ring emitter 2 and the side wall of the circular groove of the outer ring emitter 1. The annular discharge cavity 8 and the inner air supply hole 3 together constitute a cathode discharge channel. The circular groove is provided with multiple external air supply holes 4, and the other end of the outer ring emitter 1 is provided with a tail air cavity 5, which is connected to the inner air supply hole 3 and the external air supply hole 4.
[0021] Both the inner and outer surfaces of the inner and outer emitters can serve as electron emission surfaces. The emitters are connected to the left tail gas chamber through inner and outer gas supply holes to achieve a continuous supply of propellant.
[0022] The inner ring emitter 2 and the outer ring emitter 1 are two concentric rings, and the ring discharge cavity 8 is located between the two rings. The ring discharge cavity 8 and the inner gas supply hole 3 together form the discharge channel of the cathode.
[0023] The depth of the annular discharge cavity 8 (e.g.) Figure 3 As shown in L1, it occupies the entire cathode length (e.g., Figure 3 30-45% (as shown in L2); The area of the internal air supply port 3 and the external air supply port 4 extends through the entire cathode, serving as the propellant supply channel. The internal air supply port 3 is a single, independent port, while the external air supply port 4 comprises a total of seven independent air supply ports. The ratio of the sidewall area of the inner air supply port 3 to the total sidewall area of the seven outer air supply ports 4 is equal to the inner ring sidewall area of the inner ring emitter 2 (i.e., Figure 2 The area of the inner ring sidewall of the outer ring emitter 1 and the area of the outer ring sidewall of the cylindrical surface with depth L1 shown in Figure 11 (i.e., the sum of the areas of the inner and outer ring sidewalls) Figure 2 The ratio of the sum of the areas of cylindrical surface 9 and cylindrical surface 10; The tail gas chamber 5 is a countersunk hole at the tail of the cathode, and a gas damping pad 6 is installed inside to dampen the propellant flowing from the left end, ensuring that the propellant can be evenly distributed between the inner and outer gas supply holes.
[0024] The outer diameter of the cathode body 7 is between 16±4mm, and the cathode material is tantalum-tungsten.
[0025] It includes 7 external air supply holes 4, which are evenly distributed along the circumference.
[0026] The tail gas cavity 5 has a circular cross-section, and the outer circular surface of the tail gas cavity 5 is parallel to the outer circular surface of the annular discharge cavity 8.
[0027] The surfaces of both the inner ring emitter 2 and the outer ring emitter 1 serve as electron emission surfaces.
[0028] The external air supply hole 4 is tangent to the side wall of the circular groove of the outer ring emitter 1 and the outer wall of the inner ring emitter 2, respectively.
[0029] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.
[0030] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A ring-shaped porous cathode for a magnetic plasma thruster, characterized in that: The cathode body (7) includes an inner ring emitter (2) and an outer ring emitter (1). The outer ring emitter (1) is a cylinder with a circular groove at one end. The inner ring emitter (2) is annular and is disposed in the circular groove. A through hole is provided on the circular groove. The through hole inside the inner ring emitter (2) is connected to the through hole to form an inner air supply hole (3). An annular discharge cavity (8) is formed between the outer side of the inner ring emitter (2) and the side wall of the circular groove of the outer ring emitter (1). The annular discharge cavity (8) and the inner air supply hole (3) together constitute the cathode discharge channel. The circular groove is provided with multiple external air supply holes (4), and the other end of the outer ring emitter (1) is provided with a tail air chamber (5), which is connected to the inner air supply hole (3) and the external air supply hole (4).
2. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: A gas damping pad (6) is provided in the tail gas chamber (5) to dampen the propellant flowing from one end of the tail gas chamber (5) and to balance the distribution of propellant between the inner and outer gas supply holes.
3. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The central axes of the inner ring emitter (2) and the outer ring emitter (1) coincide.
4. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The depth of the annular discharge cavity (8) is 30%-45% of the total length of the cathode body (7).
5. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The ratio of the side wall area of the inner air supply hole (3) to the total side wall area of the multiple outer air supply holes (4) is equal to the ratio of the inner ring side wall area of the inner ring emitter (2) to the sum of the inner ring side wall area and the outer ring side wall area of the outer ring emitter (1).
6. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The outer diameter of the cathode body (7) is 12~20mm, and the cathode body (7) is made of tantalum-tungsten.
7. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: It includes 7 external air supply holes (4), which are evenly distributed along the circumference.
8. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The tail gas cavity (5) has a circular cross-section, and the outer circular surface of the tail gas cavity (5) is parallel to the outer circular surface of the annular discharge cavity (8).
9. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The inner and outer walls of the inner ring emitter (2) and the outer ring emitter (1) both serve as electron emission surfaces.
10. The annular porous cathode structure for a magnetic plasma thruster according to claim 1, characterized in that: The external air supply hole (4) is tangent to the side wall of the circular groove of the outer ring emitter (1) and the outer wall of the inner ring emitter (2), respectively.