Cathode based on glow discharge and hollow cathode effect

Abstract

Cathode based on glow discharge and hollow cathode effect belongs to the technical field of space electric propulsion electron source, and aims to solve the problems of high failure risk of heater and difficulty in working in oxygen environment of traditional hollow cathode.The cathode comprises a gas supply pipe, a negative electrode, a contact electrode and an extraction electrode; the contact electrode is sleeved outside the discharge chamber from the top end of the negative electrode, and the extraction electrode is sleeved outside the contact electrode from the top end; the bottom plate of the negative electrode is provided with an air inlet hole in the center and is communicated with the gas supply pipe; the top cover of the contact electrode is provided with a throttle hole in the center for maintaining the air pressure of the discharge chamber; the top cover of the extraction electrode is provided with an extraction hole; a discharge power source is loaded between the negative electrode and the contact electrode, which is used for carrying out glow discharge on the gas working medium entering the discharge chamber to generate plasma; the glow plasma generates hollow cathode effect in the cylindrical negative electrode; an extraction power source is loaded between the contact electrode and the extraction electrode, which is used for making electrons pass through the throttle hole and the extraction hole in sequence and spray to form electron emission.

Description

Technical Field

[0001] This invention relates to a cathode based on DC glow discharge and hollow cathode effect, belonging to the field of space electric propulsion electron source technology. Background Technology

[0002] Space electric thrusters generate thrust by ejecting ion beams. To prevent the positively charged ion plume from affecting the spacecraft's electrical potential, a neutralizer cathode is typically required to work in conjunction with the thruster to neutralize the plume. Cathodes can be classified into hollow cathodes, radio frequency cathodes, microwave cathodes, etc., depending on their working principle.

[0003] Air-breathing electric propulsion has become a research hotspot in the field of space electric propulsion, primarily providing mission capabilities for Earth observation and communication satellites. Air-breathing electric propulsion systems collect and compress the thin atmosphere through an air intake, and the electric thruster ionizes and accelerates the atmosphere to compensate for drag. This system uses the remaining gases from the upper atmosphere as propellants, mainly nitrogen and oxygen. In fully air-breathing electric propulsion systems, the neutralizer's flow also originates from the atmosphere. With traditional hollow cathode neutralizers, the emitter is exposed to an oxygen environment, leading to an increase in surface work function and a significant decrease in electron emission. Secondly, the oxidizing environment of low Earth orbit increases the risk of heater failure, reducing system reliability. Traditional hollow cathode neutralizers also suffer from long start-up times, high heating power, and complex structures.

[0004] While radio frequency (RF) and microwave neutralizers can overcome the limitations of hollow cathodes, RF and microwave cathodes require more complex power supply systems, are bulky, and have low power efficiency. Therefore, to address these shortcomings, a cathode that can operate in an oxidizing environment and has a simple and reliable structure is needed to ensure neutralization in air-breathing electric thrusters. Summary of the Invention

[0005] To address the problems of traditional hollow cathodes, such as high risk of heater failure and difficulty in operating in oxygen environments, this invention provides a cathode based on glow discharge and the hollow cathode effect.

[0006] The cathode based on glow discharge and hollow cathode effect of the present invention includes a gas supply pipe 1, a negative electrode 4, a contact electrode 6, and a lead electrode 8;

[0007] The negative electrode 4 is a cylindrical shape with an open top, and the concave cavity at the top of the negative electrode 4 is a discharge chamber; the contact electrode 6 and the lead electrode 8 are both cylindrical shapes with an open bottom.

[0008] The contact electrode 6 is sleeved outside the discharge chamber from the top of the negative electrode 4, and the lead electrode 8 is sleeved outside the contact electrode 6 from the top. The three have circumferential and radial working gaps, and the bottoms of the three are insulated from each other.

[0009] The bottom plate of the negative electrode 4 is provided with an air inlet hole 4-1 which communicates with the air supply pipe 1, the top cover of the holding electrode 6 is provided with a throttle hole 6-1 for maintaining the air pressure in the discharge chamber, and the top cover of the extraction electrode 8 is provided with an extraction hole 8-1;

[0010] A discharge power source VDD1 is loaded between the negative electrode 4 and the holding electrode 6 for generating glow discharge of the gas working substance entering the discharge chamber to generate plasma, and the glow plasma generates a hollow cathode effect in the cylindrical negative electrode;

[0011] An extraction power source VDD2 is loaded between the holding electrode 6 and the extraction electrode 8 for allowing electrons to pass through the throttle hole 6-1 and the extraction hole 8-1 in sequence and be emitted to form electron emission.

[0012] Preferably, the discharge power source VDD1 is a 400V-450V direct current power source, and the extraction power source VDD2 is a 20V-30V direct current power source.

[0013] Preferably, the device further comprises an insulating cap 2 and an insulating sub 3, the bottom of the negative electrode 4 is provided with a boss, the insulating sub 3 is provided with a through hole in the center, and the boss of the negative electrode 4 is extended and clamped in the through hole of the insulating sub 3, and the through hole of the insulating sub 3 is used for connecting the air supply pipe 1 and the air inlet hole 4-1 of the negative electrode 4;

[0014] The tail end of the insulating sub 3 is a two-section structure with large and small diameters, and the outer wall of the large diameter section is provided with external threads;

[0015] The insulating cap 2 is sleeved on the outside of the junction of the insulating sub 3 and the air supply pipe 1;

[0016] The insulating cap 2 is a cylindrical structure, and the internal cavity is a three-section structure with large, medium and small diameters; the inner wall of the large diameter section is provided with internal threads; the medium diameter section smoothly transitions to the small diameter section at an angle of 45°, and the small diameter section is a through hole;

[0017] The air supply pipe 1 is a two-section structure with large and small diameters, the small diameter section of the air supply pipe 1 passes through the through hole of the small diameter section of the internal cavity of the insulating cap 2, the large diameter outer wall surface of the air supply pipe 1 is in close contact with the medium diameter inner wall surface of the insulating cap 2, and the large diameter section of the air supply pipe 1 is sleeved on the outside of the small diameter section of the insulating sub 3 to realize that the top end surface of the air supply pipe 1 and the bottom surface of the medium diameter section of the insulating sub 3 are pressed together and fastened through the internal and external thread cooperation of the insulating cap 2 and the insulating sub 3.

[0018] Preferably, the junction of the air supply pipe 1 and the insulating cap 2 is sealed by applying silicone rubber, there is a gap between the large diameter section of the air supply pipe 1 and the large diameter section inside the insulating cap 2, and the thread cooperation between the inner wall of the insulating cap 2 and the tail end outer wall of the large diameter section of the insulating sub 3 is sealed by applying silicone rubber.

[0019] Preferably, the device further comprises an insulating sub 5 and an insulating sub 7, the bottom of the holding electrode 6 is insulated from the negative electrode 4 through the insulating sub 5, and the bottom of the extraction electrode 8 is insulated from the holding electrode 6 through the insulating sub 7;

[0020] The insulator two 5 and the insulator three 7 are circular, the bottom plate of the negative electrode 4 has a radial outer extension, the top edge of the outer extension of the bottom plate has a ring-shaped clamping groove, the bottom of the holding electrode 6 has an outward turning edge, and the edge of the outward turning edge has a limiting ring extending towards the bottom, the insulator two 5 is clamped between the ring-shaped clamping groove of the negative electrode 4 and the limiting ring of the holding electrode 6;

[0021] The top surface of the outward turning edge of the bottom of the holding electrode 6 is provided with a ring-shaped clamping groove near the cylinder wall, the bottom of the lead-out electrode 8 has an outward turning edge, and the edge of the outward turning edge has a limiting ring extending towards the bottom, and the insulator three 7 is clamped between the ring-shaped clamping groove of the holding electrode 6 and the limiting ring of the lead-out electrode 8.

[0022] Preferably, the insulator one 3, the negative electrode 4, the insulator two 5, the holding electrode 6, the insulator three 7 and the lead-out electrode 8 are coaxially and closely attached in sequence, are tightly fixed and sealed by the lead-out electrode bolt 11, and the lead-out electrode bolt 11 passes through the large hole of the holding electrode 6 to form a radial working gap between the lead-out electrode bolt 11 and the inner wall of the large hole of the holding electrode 6.

[0023] The insulator one 3 and the negative electrode 4 are fixed by the negative electrode bolt 9.

[0024] The insulator one 3, the negative electrode 4, the insulator two 5 and the holding electrode 6 are fixed by the holding electrode bolt 10.

[0025] Preferably, the gas supply pipe 1, the negative electrode 4, the holding electrode 6 and the lead-out electrode 8 are all made of 304 stainless steel.

[0026] Preferably, the insulating cap 2 is made of polytetrafluoroethylene material.

[0027] Preferably, the insulator one 3, the insulator two 5 and the insulator three 7 are made of alumina ceramic material.

[0028] Preferably, the diameter of the lead-out hole 8-1 is greater than the diameter of the air inlet hole 4-1, and the diameter of the air inlet hole 4-1 is greater than the diameter of the throttling hole 6-1.

[0029] The cathode based on glow discharge and hollow cathode effect provided by the application relies on the high voltage loaded between the negative electrode and the holding electrode to generate glow discharge plasma in the chamber formed between the inner surface of the negative electrode and the top end of the holding electrode, and the principle of maintaining the plasma is that the ion bombardment on the inner wall of the negative electrode generates secondary electron emission, and the lead-out voltage applied on the lead-out electrode realizes the lead-out of electrons. The cathode based on glow discharge and hollow cathode effect has simple structure, does not need a hot electrode, starts quickly, and is compatible with various working substances for discharge. Only a direct current source is needed for power supply, and the operation is simple and the system is simplified.

[0030] The negative electrode adopts a cylindrical structure, which on one hand increases the area of secondary electron emission, and on the other hand, the cathode negative glow regions overlap together when discharging, a hollow cathode effect is generated, the electrons oscillate radially in the cylindrical electric field, the probability of collision with atoms is increased, the discharge is more uniform, and the discharge plasma density is improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a sectional view of the cathode based on glow discharge and hollow cathode effect according to the present application;

[0032] Figure 2 is a right view of Figure 1 ;

[0033] Figure 3 is a left view of Figure 1 ;

[0034] Figure 4 is a perspective view of the cathode based on glow discharge and hollow cathode effect according to the present application;

[0035] Figure 5 is a schematic diagram of the cathode based on glow discharge and hollow cathode effect according to the present application.

[0036] 1, gas supply pipe, 2, insulating cap, 3, insulator one, 4, negative electrode, 5, insulator two, 6, holding electrode, 6-1, throttle hole, 7, insulator three, 8, lead-out electrode, 8-1, lead-out hole, 9, negative electrode bolt, 10, holding electrode bolt, 11, lead-out electrode bolt. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0038] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0039] The present application will be further described below with reference to the drawings and specific embodiments, but is not limited by the present application.

[0040] Specific implementation method one: the present embodiment will be described below, the cathode based on glow discharge and hollow cathode effect according to the present embodiment, including gas supply pipe 1, negative electrode 4, holding electrode 6 and lead-out electrode 8; Figures 1 to 5

[0041] ​The negative electrode 4 is a top-end open cylinder, and the top-end cavity of the negative electrode 4 is a discharge chamber; the contact electrode 6 and the lead-out electrode 8 are both bottom-end open cylinders;

[0042] The contact electrode 6 is sleeved outside the discharge chamber from the top end of the negative electrode 4, the lead-out electrode 8 is sleeved outside the contact electrode 6 from the top end, and the three have a circumferential and radial working gap, and the bottoms of the three are insulated;

[0043] The bottom plate of the negative electrode 4 is provided with an air inlet hole 4-1 in the center and is communicated with the gas supply pipe 1, the top cover of the contact electrode 6 is provided with a throttle hole 6-1 in the center for maintaining the air pressure of the discharge chamber, and the top cover of the lead-out electrode 8 is provided with a lead-out hole 8-1 in the center; the diameter of the lead-out hole 8-1 is greater than that of the air inlet hole 4-1, and the diameter of the air inlet hole 4-1 is greater than that of the throttle hole 6-1.

[0044] A discharge power source VDD1 is loaded between the negative electrode 4 and the contact electrode 6, for carrying out glow discharge on the gas working medium entering the discharge chamber to generate plasma, and the glow plasma generates a hollow cathode effect in the cylindrical negative electrode;

[0045] A lead-out power source VDD2 is loaded between the contact electrode 6 and the lead-out electrode 8, for making electrons pass through the throttle hole 6-1 and the lead-out hole 8-1 in sequence and be emitted to form electron emission.

[0046] Referring to Figure 1 and Figure 4 , further comprising an insulating cap 2 and an insulator one 3, the bottom of the negative electrode 4 is provided with a boss, the insulator one 3 is provided with a through hole in the center, and the boss of the negative electrode 4 is extended and clamped in the through hole of the insulator one 3, and the through hole of the insulator one 3 is used for connecting the gas supply pipe 1 and the air inlet hole 4-1 of the negative electrode 4;

[0047] The tail end of the insulator one 3 is a large-diameter and small-diameter two-segment structure, and the outer wall of the large-diameter segment is provided with external threads;

[0048] The insulating cap 2 is sleeved outside the junction of the insulator one 3 and the gas supply pipe 1;

[0049] The insulating cap 2 is a cylindrical structure, and the internal cavity is a large-diameter, medium-diameter and small-diameter three-segment structure; the inner wall of the large-diameter segment is provided with internal threads; the medium-diameter segment to the small-diameter segment is smoothly transitioned by 45°, and the small-diameter segment is a through hole;

[0050] The gas supply pipe 1 is a large-diameter and small-diameter two-segment structure, the small-diameter segment of the gas supply pipe 1 passes through the small-diameter segment through hole of the internal cavity of the insulating cap 2, and the large-diameter outer wall surface of the gas supply pipe 1 is attached to the medium-diameter inner wall surface of the insulating cap 2; the large-diameter segment of the gas supply pipe 1 is sleeved outside the small-diameter segment of the insulator one 3, so that the top end surface of the gas supply pipe 1 and the bottom surface of the medium-diameter segment of the insulator one are pressed together, and are fastened through the internal and external thread cooperation of the insulating cap 2 and the insulator one 3.

[0051] Further comprising insulator two 5 and insulator three 7, the bottom of the holding electrode 6 is insulated from the negative electrode 4 through the insulator two 5, and the bottom of the leading electrode 8 is insulated from the holding electrode 6 through the insulator three 7;

[0052] The insulator two 5 and the insulator three 7 are circular rings, the bottom plate of the negative electrode 4 has a radially outward extending portion, the top edge of the outward extending portion of the bottom plate has a ring-shaped clamping groove, the bottom of the holding electrode 6 has an outward turning portion, and the edge of the outward turning portion has a limiting ring extending towards the bottom, the insulator two 5 is clamped between the ring-shaped clamping groove of the negative electrode 4 and the limiting ring of the holding electrode 6;

[0053] The top surface of the outward turning portion of the bottom of the holding electrode 6 is provided with a ring-shaped clamping groove near the cylinder wall, the bottom of the leading electrode 8 has an outward turning portion, and the edge of the outward turning portion has a limiting ring extending towards the bottom, the insulator three 7 is clamped between the ring-shaped clamping groove of the holding electrode 6 and the limiting ring of the leading electrode 8.

[0054] Referring to Figure 3 , a bolt fastening scheme for the overall component is introduced, the insulator one 3, the negative electrode 4, the insulator two 5, the holding electrode 6, the insulator three 7, and the leading electrode 8 are coaxially and closely attached in sequence, are tightly pressed and fixed by the leading electrode bolt 11, and are sealed, the leading electrode bolt 11 passes through the large hole of the through hole of the holding electrode 6, so that there is a radial working gap between the leading electrode bolt 11 and the inner wall of the large hole of the holding electrode 6, that is, the electrical connection is ensured;

[0055] The insulator one 3 and the negative electrode 4 are fixed by the negative electrode bolt 9;

[0056] The insulator one 3, the negative electrode 4, the insulator two 5, and the holding electrode 6 are fixed by the holding electrode bolt 10.

[0057] Three leading electrode bolts 11, one holding electrode bolt 10, and two negative electrode bolts 9 are arranged in the embodiment.

[0058] The gas supply pipe 1, the negative electrode 4, the holding electrode 6, and the leading electrode 8 are all made of 304 stainless steel material. The insulating cap 2 is made of polytetrafluoroethylene material. The insulator one 3, the insulator two 5, and the insulator three 7 are made of aluminum oxide ceramic material.

[0059] Silicone rubber is applied to seal the cooperation part of the gas supply pipe 1 and the insulating cap 2; there is a gap between the large diameter section of the gas supply pipe 1 and the large diameter section inside the insulating cap 2; silicone rubber is applied to seal the thread cooperation part between the inner wall of the insulating cap 2 and the outer wall of the large diameter section tail of the insulator one 3.

[0060] Referring to Figure 5 , the principle of the cathode of the embodiment is described, the discharge power supply VDD1 is a 400V-450V direct current power supply, and the leading power supply VDD2 is a 20V-30V direct current power supply.

[0061] When the gas working substance is introduced into the supply pipe 1, it passes through the insulator 3, the negative electrode 4 inlet hole, the negative electrode 4 cavity, and the throttle hole of the contact electrode 6 in sequence. Under the action of the throttle hole, the gas working substance forms a high pressure in the negative electrode 4 cavity. The gas working substance is broken down to generate glow discharge plasma under the high voltage applied between the negative electrode 4 and the contact electrode 6 by the discharge power supply. Due to the cylindrical structure of the negative electrode 4, the cathode negative glow zones overlap together, and the electrons oscillate radially under the action of the electric field, increasing the probability of collision with neutral atoms and improving the plasma density. The electrons in the plasma pass through the throttle hole and the extraction hole in sequence under the extraction voltage of the extraction electrode 8, forming electron emission. The plasma in the negative electrode 4 discharge cavity is mainly maintained by the secondary electron emission caused by ion bombardment of the inner wall of the negative electrode 4.

[0062] The cathode component based on the glow discharge and the hollow cathode effect provided by the application has few components, simple structure, and small size. The high voltage applied between the negative electrode 4 and the contact electrode 6 is used to break down and start, without a heater, so that the starting is fast and the reliability is high. The secondary electron emission of the inner surface of the negative electrode 4 is used to maintain the glow discharge, without an emitter, so that the discharge of various working substances can be compatible. The negative electrode 4 adopts a cylindrical structure, the hollow cathode effect is formed during discharge, and the plasma density is improved compared with the flat plate structure. Only a direct current source is needed to maintain the work, the power supply has high efficiency, small volume, and light weight.

[0063] Although the application is described herein with reference to particular embodiments, it should be understood that these examples are merely set forth in order to explain the principles and applications of the present application. Thus, it should be understood that numerous modifications can be made to the exemplary embodiments, and that other arrangements can be devised without departing from the spirit and scope of the present application as defined by the appended claims. It will be understood that different embodiments can be combined in different ways than those described herein. It will also be understood that features described with respect to one embodiment can be used in other embodiments.

Claims

1. Cathode based on glow discharge and hollow cathode effect, characterized in that, The device comprises a gas supply pipe (1), a negative electrode (4), a touch electrode (6) and an extraction electrode (8); The negative electrode (4) is in the shape of an open-top cylinder, and the top end cavity of the negative electrode (4) is a discharge chamber; the touch electrode (6) and the extraction electrode (8) are both in the shape of an open-bottom cylinder; The touch electrode (6) is sleeved outside the discharge chamber from the top end of the negative electrode (4), and the extraction electrode (8) is sleeved outside the touch electrode (6) from the top end, and the three have circumferential and radial working gaps, and the bottoms of the three are insulated; The bottom plate of the negative electrode (4) is provided with an air inlet hole (4-1) in the center and is in communication with the gas supply pipe (1), the top cover of the touch electrode (6) is provided with a throttle hole (6-1) in the center for maintaining the air pressure of the discharge chamber, and the top cover of the extraction electrode (8) is provided with an extraction hole (8-1) in the center; A discharge power supply VDD1 is loaded between the negative electrode (4) and the touch electrode (6) for performing glow discharge on the gas working medium entering the discharge chamber to generate plasma, and the glow plasma generates a hollow cathode effect in the cylindrical negative electrode; An extraction power supply VDD2 is loaded between the touch electrode (6) and the extraction electrode (8) for allowing electrons to pass through the throttle hole (6-1) and the extraction hole (8-1) in sequence and be emitted to form electron emission.

2. Cathode based on glow discharge and hollow cathode effect according to claim 1, characterized in that, The discharge power supply VDD1 is a 400V-450V direct current power supply, and the extraction power supply VDD2 is a 20V-30V direct current power supply.

3. The cathode based on glow discharge and hollow cathode effect according to claim 1, characterized in that, The device further comprises an insulating cap (2) and an insulating sub (3), the bottom of the negative electrode (4) is provided with a boss, the insulating sub (3) is provided with a through hole in the center, the boss of the negative electrode (4) is extended and clamped in the through hole of the insulating sub (3), and the through hole of the insulating sub (3) is used for connecting the gas supply pipe (1) and the air inlet hole (4-1) of the negative electrode (4); The tail end of the insulating sub (3) is in a large-diameter and small-diameter two-section structure, and the outer wall of the large-diameter section is provided with external threads; The insulating cap (2) is sleeved outside the junction of the insulating sub (3) and the gas supply pipe (1); The insulating cap (2) is in a cylindrical structure, and the internal cavity is in a large-diameter, medium-diameter and small-diameter three-section structure; the inner wall of the large-diameter section is provided with internal threads; the medium-diameter section to the small-diameter section is smoothly transitioned at an angle of 45°, and the small-diameter section is a through hole; The gas supply pipe (1) is in a large-diameter and small-diameter two-section structure, the small-diameter section of the gas supply pipe (1) passes through the small-diameter section through hole of the internal cavity of the insulating cap (2), the large-diameter outer wall surface of the gas supply pipe (1) is attached to the medium-diameter inner wall surface of the insulating cap (2), and the large-diameter section of the gas supply pipe (1) is sleeved outside the small-diameter section of the insulating sub (3) to realize that the top end surface of the gas supply pipe (1) is pressed together with the bottom surface of the medium-diameter section of the insulating sub (3) and is fastened through the internal and external thread cooperation of the insulating cap (2) and the insulating sub (3).

4. Cathode based on glow discharge and hollow cathode effect according to claim 3, characterized in that, Silicone rubber is applied to seal the cooperation part of the gas supply pipe (1) and the insulating cap (2); there is a gap between the large-diameter section of the gas supply pipe (1) and the internal large-diameter section of the insulating cap (2); and silicone rubber is applied to seal the thread cooperation part of the inner wall of the insulating cap (2) and the outer wall of the large-diameter section of the insulating sub (3).

5. The cathode based on glow discharge and hollow cathode effect according to claim 3, characterized in that, The device further comprises an insulating sub (5) and an insulating sub (7), the bottom of the touch electrode (6) is insulated from the negative electrode (4) through the insulating sub (5), and the bottom of the extraction electrode (8) is insulated from the touch electrode (6) through the insulating sub (7). The insulator two (5) and the insulator three (7) are circular, the bottom plate of the negative electrode (4) has a radial outward extension, the top edge of the outward extension of the bottom plate has a ring-shaped clamping groove, the bottom of the holding electrode (6) has an outward extension, and the edge of the outward extension has a limiting ring extending in the direction of the bottom, the insulator two (5) is clamped between the ring-shaped clamping groove of the negative electrode (4) and the limiting ring of the holding electrode (6); The top surface of the outward extension of the bottom of the holding electrode (6) is provided with a ring-shaped clamping groove near the cylinder wall, the bottom of the lead-out electrode (8) has an outward extension, and the edge of the outward extension has a limiting ring extending in the direction of the bottom, the insulator three (7) is clamped between the ring-shaped clamping groove of the holding electrode (6) and the limiting ring of the lead-out electrode (8).

6. Cathode based on glow discharge and hollow cathode effect according to claim 5, characterized in that, The insulator one (3), the negative electrode (4), the insulator two (5), the holding electrode (6), the insulator three (7), and the lead-out electrode (8) are coaxially and closely attached in sequence, are tightly fixed and sealed by the lead-out electrode bolt (11), the lead-out electrode bolt (11) passes through the through hole of the holding electrode (6) to form a large hole, so that there is a radial working gap between the lead-out electrode bolt (11) and the inner wall of the large hole of the holding electrode (6); The insulator one (3) and the negative electrode (4) are fixed by the negative electrode bolt (9). The insulator one (3), the negative electrode (4), the insulator two (5), and the holding electrode (6) are fixed by the holding electrode bolt (10).

7. The cathode based on glow discharge and hollow cathode effect according to claim 5, characterized in that, The gas supply pipe (1), the negative electrode (4), the holding electrode (6), and the lead-out electrode (8) are all made of 304 stainless steel.

8. The cathode based on glow discharge and hollow cathode effect according to claim 5, characterized in that, The insulating cap (2) is made of polytetrafluoroethylene material.

9. The cathode based on glow discharge and hollow cathode effect according to claim 5, characterized in that, The insulator one (3), the insulator two (5), and the insulator three (7) are all made of alumina ceramic material.

10. The cathode based on glow discharge and hollow cathode effect according to claim 1, characterized in that, The diameter of the lead-out hole (8-1) is greater than the diameter of the air inlet hole (4-1), and the diameter of the air inlet hole (4-1) is greater than the diameter of the throttle hole (6-1).

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