Miniature DC ion thruster based on glow discharge cathode

Abstract

This invention relates to a miniature DC ion thruster based on a glow discharge cathode, belonging to the field of miniature DC ion thrusters. The invention addresses the problems of complex hollow cathode structures, difficulty in miniaturization, high operating temperatures, and short lifespan of tungsten filament cathodes in existing DC ion thrusters. The invention comprises a glow discharge cathode assembly, an anode assembly, a gate assembly, a permanent magnet assembly, a mounting base, and a housing. The mounting base is located at the bottom opening of the housing. Inside the housing, the permanent magnet assembly, anode assembly, and glow discharge cathode assembly are sequentially housed from the outside in. The gate assembly is located downstream of the anode assembly. The glow discharge cathode assembly is mounted on the mounting base and extends from its central hole. The glow discharge cathode assembly initially ionizes the working gas; electrons are absorbed by the anode assembly. The unionized neutral gas in the glow discharge cathode assembly is further ionized in the discharge chamber, and the ions in the discharge chamber are accelerated and ejected by an ion optics system.

Description

Technical Field

[0001] This invention relates to a miniature DC ion thruster based on a glow discharge cathode, and belongs to the field of miniature DC ion thrusters. Background Technology

[0002] Ion thrusters are among the most technologically mature and widely used electric propulsion devices, boasting advantages such as high specific impulse, high efficiency, and a wide range of adjustable thrust and specific impulse. Based on the plasma generation method, ion thrusters can be categorized into DC ion thrusters, radio frequency (RF) ion thrusters, and microwave ion thrusters. DC ion thrusters are widely studied due to their simple and reliable structure and power supply module; while RF and microwave ion thrusters require additional RF and microwave sources, resulting in lower power efficiency and increased system size and weight.

[0003] A DC ion thruster mainly consists of a main cathode, an anode, a magnetic field, and an ion optical system. Primary electrons emitted from the main cathode, under the influence of an electromagnetic field, eventually reach the anode. During this process, the electrons collide with the propellant, ionizing and generating plasma. This plasma is then accelerated and ejected through the ion optical system, creating a reaction force. Currently, the main cathodes of DC ion thrusters are primarily hollow cathodes made of barium tungsten and lanthanum hexaboride, which have complex structures and are difficult to adapt to the size of micro-ion thrusters. Secondly, relying on thermionic emission, they have strong current emission capabilities but operate at high temperatures, typically exceeding 1000℃. The maximum temperature resistance of the samarium-cobalt permanent magnets in micro-DC ion thrusters is generally only 350℃. Prolonged operation of the thruster will cause the permanent magnets to demagnetize, disrupting the designed magnetic field. Tungsten filament cathodes have also been used as main cathodes in micro-DC ion thrusters, but they also suffer from high operating temperatures and short lifespans.

[0004] Therefore, to address the above shortcomings, a cathode that is small in size, simple in structure, operates at low temperature, and has a certain service life is needed as the main cathode of the micro DC ion thruster. Summary of the Invention

[0005] To address the problems of complex and difficult-to-miniaturize traditional hollow cathode structures, high operating temperatures, and short service life of tungsten filament cathodes in existing DC ion thrusters, this invention provides a miniature DC ion thruster based on a glow discharge cathode.

[0006] The micro DC ion thruster based on glow discharge cathode of the present invention includes glow discharge cathode assembly, anode assembly, gate assembly, permanent magnet assembly, mounting base 13 and housing 16; mounting base 13 is disposed at the bottom opening end of housing 16, and permanent magnet assembly, anode assembly and glow discharge cathode assembly are sequentially arranged inside housing 16 from the outside to the inside, and gate assembly is disposed downstream of anode assembly;

[0007] The glow cathode assembly is mounted on the mounting base 13 and extends from its central hole. The glow cathode assembly initially ionizes the working gas, and the electrons are absorbed by the anode assembly. The unionized neutral gas in the glow cathode assembly is further ionized in the discharge chamber, and the ions in the discharge chamber are accelerated and ejected by the ion optical system.

[0008] The glow cathode assembly includes a gas supply pipe 1, an insulating cap 2, a negative electrode insulator 3, a negative electrode 4, a contact electrode insulator 5, and a contact electrode 6; the gas supply pipe 1 is located between the insulating cap 2 and the negative electrode insulator 3, and is pressed together by the internal thread of the insulating cap 2 and the external thread of the negative electrode insulator 3.

[0009] The bottom of the negative electrode 4 of the glow cathode is provided with an air inlet 4-1 for connecting the gas supply pipe 1 and the cathode chamber; the top of the contact electrode 6 is provided with a throttling orifice 6-1 for gas throttling to maintain a higher gas pressure in the cathode chamber.

[0010] The negative pole 4 and the gas supply pipe 1 are insulated by the negative pole insulator 3; the contact pole 6 and the negative pole 4 are insulated by the contact pole insulator 5.

[0011] Preferably, the contact electrode 6 has a cylindrical structure and is provided with a throttling orifice 6-1, so that a higher gas pressure is formed in the glow cathode discharge chamber;

[0012] The throttling orifice 6-1 is configured as follows:

[0013] Method 1: A single hole is provided on the top of the contact electrode 6;

[0014] Method 2: Multiple small holes are provided on the top of the contact electrode 6, and the diameter of the small holes is smaller than the diameter of a single hole in Method 1;

[0015] Method 3: A small hole is provided at the top of the contact electrode 6 to draw out electrons and a small amount of neutral gas; a ring of small holes is provided on the wall of the contact electrode 6 to draw out most of the neutral gas, so that it collides with electrons near the anode outside the wall.

[0016] Preferably, it also includes a baffle 10, which is disposed downstream of the cathode throttling orifice 6-1 and fixed on the contact electrode 6, for homogenizing the unionized neutral gas of the glow cathode.

[0017] Preferably, the anode assembly includes an anode insulator 7 and an anode 8;

[0018] The anode 8 is cylindrical and is sleeved outside the contact electrode 6. The interior of the anode 8 forms a thruster discharge chamber.

[0019] The bottom inward flange of the anode 8 is set on the bottom outward flange of the contact electrode 6, and the two are insulated by the anode insulator 7. The anode insulator 7 is cylindrical, and the anode 8 and the anode insulator 7 are coaxial. The anode 8, the contact electrode 6 and the negative electrode 4 are fixed together on the mounting base 13.

[0020] Preferably, the permanent magnet assembly includes a permanent magnet support frame 14 and a permanent magnet 15. The permanent magnet 15 is annular and is sleeved on the outside of the anode 8. The bottom end of the permanent magnet 15 is mounted on the permanent magnet support frame 14. The permanent magnet support frame 14 is fixed on the mounting base 13. The permanent magnet support frame 14 is coaxial with the outer shell 16, and there is a gap between the two.

[0021] Preferably, the gate assembly includes a screen gate 11, an acceleration gate 12, and a gate insulator 9; the top of the cylindrical anode insulator 7 is a flange structure, the screen gate 11 and the acceleration gate 12 are fixed on the flange, and are electrically insulated and positioned by the gate insulator 9.

[0022] Preferably, the glow discharge cathode assembly is fixed to the mounting base 13 by two negative electrode bolts and one contact electrode bolt;

[0023] The bottom inward-turned edge of the anode 8 is provided with three threaded holes, and the anode bolts are passed through the through holes of the glow discharge cathode assembly to fix it to the mounting base 13;

[0024] The glow discharge cathode assembly has three through holes set on the outward-turned edge of the bottom of the contact electrode 6 cylinder. The inner diameter of the through holes is larger than the outer diameter of the anode bolt, and there is a gap between the through holes and the anode bolt.

[0025] The bottom of the permanent magnet support frame 14 is fixed to the mounting base 13 by a number of permanent magnet bolts;

[0026] The bottom of the outer casing 16 is fixed to the mounting base 13 by a number of outer casing bolts;

[0027] The anode bolt, negative electrode bolt, and contact electrode bolt are conductive, respectively connected to the corresponding anode, negative electrode, and contact electrode.

[0028] Preferably, the gas supply pipe 1, negative electrode 4, contact electrode 6, anode 8 and outer casing 16 are made of 304 stainless steel.

[0029] The negative pole insulator 3, the contact pole insulator 5, the anode insulator 7, and the gate insulator 9 are made of alumina ceramic material;

[0030] The mounting base 13 and the permanent magnet support frame 14 are made of aluminum alloy.

[0031] The screen 11 and the acceleration grid 12 are made of stainless steel or molybdenum.

[0032] The permanent magnet 15 is made of high-temperature resistant samarium cobalt material.

[0033] Preferably, it also includes a cathode power supply, a discharge power supply, a screen grid power supply, and an acceleration grid power supply;

[0034] The negative electrode 4 of the glow cathode is connected to the negative electrode of the cathode power supply, the contact electrode 6 is connected to the positive electrode of the cathode power supply and the negative electrode of the discharge power supply, and the anode is connected to the positive electrode of the discharge power supply.

[0035] The screen grid 11 is connected to the positive terminal of the screen grid power supply, and the acceleration grid 12 is connected to the negative terminal of the acceleration grid power supply. The negative terminal of the screen grid power supply and the positive terminal of the acceleration grid power supply are grounded, so that the screen grid has a positive potential relative to ground and the acceleration grid has a negative potential relative to ground.

[0036] The working principle of the micro DC ion thruster based on glow discharge cathode provided by this invention is as follows: When an inert gas working medium, such as xenon or krypton, is introduced into the gas supply pipe, it passes sequentially through the negative electrode insulator, the negative electrode inlet, and the cathode discharge chamber. Under high voltage between the negative electrode and the contact electrode, a glow discharge plasma is generated. Electrons in the plasma pass through the contact electrode throttling orifice under the action of the anode electric field and enter the thruster discharge chamber. Under the action of the electromagnetic field, they finally reach the anode. During their movement, they collide with unionized neutral atoms to generate secondary ionization. Ions in the plasma are accelerated and ejected under the action of the grid electric field to generate thrust.

[0037] The beneficial effects of this invention are as follows: The micro DC ion thruster based on a glow discharge cathode provided by this invention relies on a glow discharge cathode as the main cathode to generate primordial electrons. This glow discharge cathode has a simple structure, making it suitable for micro ion thrusters; the main cathode relies on high-voltage cold start, eliminating the need for a heater and resulting in a short ignition time; the main cathode operates in glow discharge mode at a low temperature, allowing the thruster to operate for extended periods while maintaining the permanent magnet's non-demagnetization; and the electrons and unionized neutral atoms generated by the glow discharge cathode are used for secondary ionization in the thruster's discharge chamber, simplifying the gas supply pipeline while improving the working fluid utilization rate. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the miniature DC ion thruster based on the glow discharge cathode described in this invention;

[0039] Figure 2 yes Figure 1 The left view;

[0040] Figure 3 This is a schematic diagram of the glow discharge cathode mounting structure;

[0041] Figure 4 This is a schematic diagram of the contact electrode of a glow discharge cathode;

[0042] Figure 5 This is a schematic diagram of another structure of the contact electrode of a glow discharge cathode;

[0043] Figure 6 This is a circuit diagram of a miniature DC ion thruster based on a glow discharge cathode.

[0044] 1. Air supply pipe; 2. Insulating cap; 3. Negative pole insulator; 4. Negative pole; 4-1. Air inlet; 5. Contact pole insulator; 6. Contact pole; 6-1. Throttling orifice; 7. Anode insulator; 8. Anode; 9. Gate insulator; 10. Baffle; 11. Screen grid; 12. Acceleration grid; 13. Mounting base; 14. Permanent magnet support frame; 15. Permanent magnet; 16. Outer shell;

[0045] 17-1, No. 1 outer casing bolt; 17-2, No. 2 outer casing bolt; 17-3, No. 3 outer casing bolt; 17-4, No. 4 outer casing bolt;

[0046] 18-1, No. 1 permanent magnet bolt; 18-2, No. 2 permanent magnet bolt; 18-3, No. 3 permanent magnet bolt; 18-4, No. 4 permanent magnet bolt;

[0047] 19-1, No. 1 anode bolt; 19-2, No. 2 anode bolt; 19-3, No. 3 anode bolt;

[0048] 20-1, No. 1 negative electrode bolt; 20-2, No. 2 negative electrode bolt; 20-3, contact electrode bolt. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0052] Specific Implementation Method 1: The following is combined with... Figures 1 to 6 This embodiment describes a miniature DC ion thruster based on a glow discharge cathode, comprising a glow discharge cathode assembly, an anode assembly, a gate assembly, a permanent magnet assembly, a mounting base 13, and a housing 16. The mounting base 13 is located at the bottom opening of the housing 16. Inside the housing 16, the permanent magnet assembly, the anode assembly, and the glow discharge cathode assembly are sequentially housed from the outside to the inside. The gate assembly is located downstream of the anode assembly.

[0053] The glow cathode assembly is mounted on the mounting base 13 and extends from its central hole. The glow cathode assembly initially ionizes the working gas, and the electrons are absorbed by the anode assembly. The unionized neutral gas in the glow cathode assembly is further ionized in the discharge chamber, and the ions in the discharge chamber are accelerated and ejected by the ion optical system.

[0054] The glow discharge cathode assembly includes a gas supply pipe 1, an insulating cap 2, a negative electrode insulator 3, a negative electrode 4, a contact electrode insulator 5, and a contact electrode 6.

[0055] The bottom of the negative electrode 4 of the glow cathode is provided with an air inlet 4-1 for connecting the gas supply channel and the cathode chamber; the top of the contact electrode 6 is provided with a throttling orifice 6-1 for gas throttling to maintain a higher gas pressure in the cathode chamber.

[0056] The negative pole 4 and the gas supply pipe 1 are insulated by the negative pole insulator 3; the contact pole 6 and the negative pole 4 are insulated by the contact pole insulator 5.

[0057] The anode assembly includes an anode insulator 7 and an anode 8.

[0058] Anode 8 and anode insulator 7 are coaxial, and anode insulator 7 is used for insulation between contact pole 6 and anode 8.

[0059] Three threaded holes are provided at the bottom of the anode, and three anode bolts 19-1, 19-2, and 19-3 are passed through the through holes of the glow discharge cathode assembly and fixed to the mounting base 13.

[0060] The bolts are conductors and are electrically connected to the electrodes, that is, the anode bolt, the negative electrode bolt, and the contact electrode bolt are conductors and are electrically connected to the corresponding anode, negative electrode, and contact electrode, respectively.

[0061] A baffle 10 is provided downstream of the cathode throttling orifice 6-1. The baffle 10 can be spot welded to the contact electrode 6 to homogenize the unionized neutral gas of the glow discharge cathode, reduce the axial velocity of the neutral gas, and increase the probability of collision with electrons.

[0062] The contact electrode 6 has a cylindrical structure and is provided with a throttling orifice 6-1. The throttling orifice 6-1 is configured as follows:

[0063] Method 1: A single hole is provided at the top of the contact electrode 6, which is used to draw out both electrons and neutral gas.

[0064] To further improve the utilization rate of neutral gas, the throttling orifice of the contact electrode 6 can be configured as multiple small orifices, as in methods two and three.

[0065] Method 2: Multiple small holes are provided on the top of the contact electrode 6. The throttling orifice 6-1 at the top of the contact electrode 6 can be configured as multiple throttling orifices 6-1, such as... Figure 5As shown, this design reduces losses in the central gas due to high axial velocity, and the high plasma density region of the cathode glow discharge is located near the tip of the contact electrode 6, making electron extraction easier. The multiple orifices have the same diameter, which is smaller than the diameter of the throttling orifice 6-1 in the case of a single orifice.

[0066] Method 3: A small hole is provided at the top of the contact electrode 6, and a ring of small holes is provided on the wall of the contact electrode 6, such as... Figure 4 As shown, the small hole at the top is mainly used to draw out electrons and a small amount of neutral gas, while the several small holes on the side wall are mainly used to draw out neutral gas. On the one hand, this reduces the gas flow rate and increases the residence time in the discharge chamber. On the other hand, the working gas drawn out from the small holes on the side wall of the contact electrode 6 approaches the anode and collides with electrons, thereby improving the ionization efficiency of the discharge chamber.

[0067] The permanent magnet 15 assembly includes a permanent magnet support frame 14 and a permanent magnet 15.

[0068] Several annular permanent magnets 15 are arranged on the outside of the anode insulator 7 and mounted on the permanent magnet support frame 14;

[0069] The permanent magnet support frame 14 is coaxial with the outer shell 16, and there is a gap between them.

[0070] The gate assembly includes a screen gate 11, an acceleration gate 12, and a plurality of gate insulators 9. The screen gate 11 and the acceleration gate 12 are fixed to the top of the anode insulator and are insulated and positioned by the gate insulators 9.

[0071] The various structures are connected and fixed to the mounting base 13 by bolts, specifically as follows:

[0072] The glow discharge cathode assembly is fixed to the mounting base 13 by two negative electrode bolts and one contact electrode bolt. Two threaded holes are provided at the bottom of the negative electrode 4 for connecting and fixing the first negative electrode bolt 20-1 and the second negative electrode bolt 20-2. A threaded hole is provided at the bottom of the contact electrode 6 for connecting and fixing the contact electrode bolt 20-3. The mounting structure of the glow discharge cathode is as follows: Figure 3 As shown.

[0073] The bottom inward-turned edge of the anode 8 is provided with three threaded holes, and the anode bolts are passed through the through holes of the glow discharge cathode assembly to fix it to the mounting base 13;

[0074] The glow discharge cathode assembly has three through holes located on the outward-facing edge of the bottom of the contact electrode 6 cylinder. The inner diameter of the through holes is larger than the outer diameter of the anode bolts, and there is a gap between the through holes and the anode bolts. The anode is fixed to the mounting base 13 by passing through the through holes of the glow discharge cathode assembly using three anode bolts, with a gap between the through holes and the anode bolts. The three anode bolts are anode bolt No. 1 19-1, anode bolt No. 2 19-2, and anode bolt No. 3 19-3.

[0075] The bottom of the permanent magnet support frame 14 is fixed to the mounting base 13 by a number of permanent magnet bolts; in this embodiment, four permanent magnet bolts are set as permanent magnet bolt No. 1 18-1, permanent magnet bolt No. 2 18-2, permanent magnet bolt No. 3 18-3 and permanent magnet bolt No. 4 18-4.

[0076] The bottom of the outer casing 16 is fixed to the mounting base 13 by a number of outer casing bolts. In this embodiment, four outer casing bolts are provided, namely outer casing bolt No. 1 17-1, outer casing bolt No. 2 17-2, outer casing bolt No. 3 17-3 and outer casing bolt No. 4 17-4.

[0077] The gas supply pipe 1, negative electrode 4, contact electrode 6, anode 8, and outer casing 16 are all made of 304 stainless steel.

[0078] The negative pole insulator 3, the contact pole insulator 5, the anode insulator and the gate insulator are made of alumina ceramic material;

[0079] The mounting base 13 and the permanent magnet support frame 14 are made of aluminum alloy.

[0080] The screen 11 and the acceleration grid 12 are made of stainless steel or molybdenum.

[0081] The permanent magnet 15 is made of high-temperature resistant samarium cobalt material, with a maximum allowable operating temperature of 350℃.

[0082] See Figure 6 The negative electrode 4 of the glow cathode is connected to the negative electrode of the cathode power supply, the contact electrode 6 is connected to the positive electrode of the cathode power supply and the negative electrode of the discharge power supply, and the anode is connected to the positive electrode of the discharge power supply.

[0083] The screen grid 11 is connected to the positive terminal of the screen grid power supply, and the acceleration grid 12 is connected to the negative terminal of the acceleration grid power supply. The negative terminal of the screen grid power supply and the positive terminal of the acceleration grid power supply are grounded, so that the screen grid has a positive potential relative to ground and the acceleration grid has a negative potential relative to ground.

[0084] Unlike when a hollow cathode is used as the main cathode of an ion thruster, the grid 11 needs to be connected to the contact electrode 6 of the glow cathode via a wire to keep them at the same potential.

[0085] The ion thruster based on glow discharge provided by this invention operates by an inert gas working medium through a gas supply pipe 1 and a negative electrode inlet 4-1 of a negative electrode insulator 3. Under the action of a throttling orifice 6-1, a high pressure is formed in the cathode chamber. Relying on the high voltage applied to the negative electrode 4 and the contact electrode 6, the neutral gas is broken down to generate glow discharge plasma, completing the cathode ignition process. After the glow cathode stabilizes, the discharge power supply is turned on. Electrons in the plasma inside the glow cathode enter the discharge chamber through the throttling orifice 6-1 under the action of the anode electric field. The electrons are confined by the magnetic field, increasing their conduction path. During their movement, they undergo secondary collisions with the unionized neutral atoms of the glow cathode, resulting in secondary ionization. The lower-energy electrons generated by the collisions are absorbed by the anode 8 and form a complete circuit, completing the thruster ignition process. After the thruster discharge stabilizes, the grid power supply and the acceleration grid power supply are turned on. The ions in the discharge chamber are accelerated and ejected by the ion optical system, forming a reaction thrust, completing the thruster plume extraction process.

[0086] The micro DC ion thruster based on glow discharge cathode provided by this invention generates primordial electrons by glow discharge cathode. This cathode consists of a cylindrical negative electrode 4 and a contact electrode 6, with few parts, simple structure, and easy miniaturization. This cathode relies on the application of high voltage for cold start, without the need for a heater, and has a fast instantaneous start-up response. This cathode operates in glow discharge mode with a low operating temperature, which greatly reduces the risk of permanent magnet demagnetization, especially when hollow cathode and tungsten filament cathode are used as the main cathode, thus allowing the thruster to work for a long time.

[0087] The micro-thruster of the present invention can use inert gas working fluids such as xenon, krypton, and argon as propellants, as well as unconventional propellants such as oxygen and nitrogen.

[0088] The micro DC ion thruster based on a glow discharge cathode provided by this invention uses only one gas supply. The gaseous working fluid first passes through the glow discharge cathode, generating a glow discharge, which is the primary ionization and produces primordial electrons. The unionized neutral gas enters the discharge chamber through the throttling orifice 6-1. Under the action of the downstream baffle 10, the neutral atoms diffuse radially and collide with the primordial electrons to undergo secondary ionization. On the one hand, this simplifies the gas supply pipeline and reduces system complexity; on the other hand, the secondary ionization of the working fluid in the discharge chamber improves the utilization rate of the working fluid.

[0089] The micro DC ion thruster based on glow discharge cathode provided by this invention can use glow discharge cathode as a neutralizer for plume neutralization, or it can use tungsten filament cathode with a similar emission current level as a neutralizer for neutralization.

[0090] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A micro DC ion thruster based on a glow discharge cathode, characterized in that, The glow cathode assembly, the anode assembly, the grid assembly, the permanent magnet assembly, the mounting base (13) and the shell (16); the mounting base (13) is arranged at the bottom opening end of the shell (16), and the inside of the shell (16) is sequentially sleeved with the permanent magnet assembly, the anode assembly and the glow cathode assembly from outside to inside, and the grid assembly is arranged downstream of the anode assembly; The glow cathode assembly is arranged on the mounting base (13) and extends from the center hole thereof, the glow cathode assembly preliminarily ionizes the working gas, the electrons are absorbed by the anode assembly, and the neutral gas not ionized by the glow cathode assembly is further ionized in the discharge chamber, and the ions in the discharge chamber are accelerated and sprayed out by the ion optical system; The glow cathode assembly comprises a gas supply pipe (1), an insulating cap (2), a negative electrode insulator (3), a negative electrode (4), a holding electrode insulator (5) and a holding electrode (6); the gas supply pipe (1) is located between the insulating cap (2) and the negative electrode insulator (3) and is compressed by the cooperation of the internal threads of the insulating cap (2) and the external threads of the negative electrode insulator (3). The bottom of the negative electrode (4) of the glow cathode is provided with an air inlet hole (4-1) for connecting the gas supply pipe (1) and the cathode chamber; the top end of the holding electrode (6) is provided with a throttle hole (6-1) for throttling the gas to maintain a higher gas pressure in the cathode chamber. The negative electrode (4) and the gas supply pipe (1) are insulated by the negative electrode insulator (3); the holding electrode (6) and the negative electrode (4) are insulated by the holding electrode insulator (5).

2. The glow discharge cathode-based micro-DC ion thruster according to claim 1, wherein The holding electrode (6) is in a cylindrical structure, and the holding electrode (6) is provided with a throttle hole (6-1) to form a higher gas pressure in the glow cathode discharge chamber; The throttle hole (6-1) is arranged in the following ways: Way one, a single hole is arranged at the top of the holding electrode (6); Way two, a plurality of small holes are arranged at the top of the holding electrode (6), and the diameters of the small holes are smaller than that of the single hole in way one; Way three, a small hole is arranged at the top of the holding electrode (6) for leading out electrons and a small part of neutral gas; a ring of small holes is arranged on the wall of the holding electrode (6) for leading out most of the neutral gas to collide with the electrons near the anode outside the wall.

3. The glow discharge cathode-based micro-DC ion thruster according to claim 2, wherein A baffle (10) is further arranged downstream of the cathode throttle hole (6-1), the baffle (10) is fixed on the holding electrode (6), and the baffle (10) is used for homogenizing the neutral gas not ionized by the glow cathode.

4. The glow discharge cathode-based micro-DC ion thruster according to claim 3, wherein The anode assembly comprises an anode insulator (7) and an anode (8); The anode (8) is in a cylindrical structure, the anode (8) is sleeved outside the holding electrode (6), and the inside of the anode (8) forms a thruster discharge chamber; The bottom of the anode (8) is inwardly turned along the outwardly turned edge of the holding electrode (6), and the two are insulated by the anode insulator (7), the anode insulator (7) is in a cylindrical structure, the anode (8) and the anode insulator (7) are coaxial, and the anode (8), the holding electrode (6) and the negative electrode (4) are fixed on the mounting base (13).

5. The glow discharge cathode-based micro-DC ion thruster according to claim 4, wherein The permanent magnet assembly comprises a permanent magnet support frame (14) and a permanent magnet (15), the permanent magnet (15) is annular, the permanent magnet (15) is sleeved outside the anode (8), the bottom end surface of the permanent magnet (15) is mounted on the permanent magnet support frame (14), the permanent magnet support frame (14) is fixed on the mounting base (13), the permanent magnet support frame (14) is coaxial with the shell (16), and a gap exists between the permanent magnet support frame (14) and the shell (16).

6. The glow discharge cathode-based micro-DC ion thruster according to claim 5, wherein The grid assembly comprises a screen grid (11), an accelerating grid (12) and a grid insulator (9); the cylindrical top end of the anode insulator (7) is in a flange structure, the screen grid (11) and the accelerating grid (12) are fixed on the flange, and the screen grid (11) and the accelerating grid (12) are electrically insulated and positioned by the grid insulator (9).

7. The glow discharge cathode-based micro-DC ion thruster according to claim 5, wherein The glow cathode assembly is fixed on the mounting base (13) by two negative electrode bolts and one touch electrode bolt; Three threaded holes are arranged on the bottom of the anode (8) in an outward turning manner, and the anode (8) is fixed on the mounting base (13) by three anode bolts penetrating through the through holes of the glow cathode assembly; The through holes of the glow cathode assembly are three through holes arranged on the bottom of the touch electrode (6) in an outward turning manner, the inner diameter of the through holes is greater than the outer diameter of the anode bolt, and a gap exists between the through holes and the anode bolt; The bottom of the permanent magnet support frame (14) is fixed on the mounting base (13) by a plurality of permanent magnet bolts; The bottom of the shell (16) is fixed on the mounting base (13) by a plurality of shell bolts; The anode bolt, the negative electrode bolt and the touch electrode bolt are conductive bodies and are electrically connected to the corresponding anode, negative electrode and touch electrode respectively.

8. The glow discharge cathode-based micro-DC ion thruster according to claim 5, wherein The gas supply pipe (1), the negative electrode (4), the touch electrode (6), the anode (8) and the shell (16) are made of 304 stainless steel; The negative electrode insulator (3), the touch electrode insulator (5), the anode insulator (7) and the grid insulator (9) are made of alumina ceramic material; The mounting base (13) and the permanent magnet support frame (14) are made of aluminum alloy material; The screen grid (11) and the accelerating grid (12) are made of stainless steel or molybdenum material; The permanent magnet (15) is made of high-temperature-resistant samarium-cobalt material.

9. The glow discharge cathode-based micro-DC ion thruster according to claim 5, wherein A cathode power supply, a discharge power supply, a screen grid power supply and an accelerating grid power supply are further included; The negative electrode (4) of the glow cathode is connected to the negative electrode of the cathode power supply, the touch electrode (6) is connected to the positive electrode of the cathode power supply and the negative electrode of the discharge power supply, and the anode is connected to the positive electrode of the discharge power supply; The screen grid (11) is connected to the positive electrode of the screen grid power supply, the accelerating grid (12) is connected to the negative electrode of the accelerating grid power supply, the negative electrode of the screen grid power supply and the positive electrode of the accelerating grid power supply are grounded, so that the screen grid has a positive potential to the ground and the accelerating grid has a negative potential to the ground.

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