CN107979910A - Active control method for surface potential of dielectric material in high vacuum environment - Google Patents

Abstract

The invention discloses a method for actively controlling the surface potential of a dielectric material in a high-vacuum environment. The discharge process is carried out in a high-vacuum environment. The discharge process includes using a microwave power supply to supply power to a magnetron to generate 2.45GHz electromagnetic waves. The electromagnetic waves are in TEM mode. It is fed through the coaxial waveguide and fed into the microwave coaxial antenna through the microwave transmission system. The lower end of the microwave coaxial antenna is located in the plasma chamber of the plasma source body. The body completes the electricity elimination process in the vacuum chamber; in a high vacuum environment, the microwave coaxial antenna breaks down the working gas in the plasma chamber to form plasma, and the ring-shaped permanent magnet steel located in the plasma chamber is used to generate 0.0875 Tess The magnetic field is pulled, and a high-density electron cyclotron resonance plasma is formed under the action of the magnetic field, which diffuses into the environment of the workpiece to be processed through the plasma regulating plate, and realizes the active adjustment of the surface charge of the medium.

Description

Active Control Method of Dielectric Material Surface Potential in High Vacuum Environment

technical field

The invention belongs to the field of scientific research on the interaction between plasma and materials, and in particular relates to an active control method for the surface potential of a dielectric material in a high-vacuum environment.

Background technique

During the operation of the spacecraft in orbit, its surface is affected by space plasma, high-energy electrons, solar radiation, space charged dust and other environments, and electrostatic charge accumulation and leakage may occur. This charging and discharging process may cause the breakdown of spacecraft materials, the degradation of material surface properties, and the performance degradation or damage of solar cells, electronic devices, and optical sensors; at the same time, the strong electromagnetic pulses generated by this charging and discharging process will seriously interfere with spaceflight. Abnormalities, failures, failures, and even scrapping of the spacecraft will seriously affect the execution of major space missions. Therefore, effective control of the surface potential of spacecraft is of great significance to ensure the safe and stable operation of my country's spacecraft in orbit.

The harsh environment of the space is complex and changeable (such as ultra-low temperature, extremely low vacuum, high-energy electron ion irradiation, etc.), and the commonly available ground static removal methods (such as humidified air, corona discharge, etc.) will not be used. The current control methods for the surface potential of the medium are mainly divided into passive control and active control. Compared with the former active control, it is more flexible, effective and thorough. There are mainly three types of charged particle beams that are usually emitted: electron beams, ion beams, and plasma beams, wherein both electron beams and ion beams are single-electricity particle streams. The International Space Station (ISS) uses a hollow cathode assembly that emits electrons. The electron beam emitted by it provides a low-impedance path between the space station and the space plasma environment, reducing and controlling the surface potential of the space station. This hollow cathode assembly emits electrons Strong ability, but less ions, higher power consumption, and incomplete neutralization. The European Space Agency has proposed an active control method for the ion source, which uses liquid metal to evaporate, ionize, and be accelerated by the voltage of the accelerator to form an ion beam. However, the structure of this ion source is relatively complicated, and it can only neutralize the negative potential. , can not neutralize the positive potential, and will bring unfavorable material pollution and so on. Due to the harsh and changeable space environment and the frequent changes in the position of the aircraft, the potential amplitude and polarity of the dielectric material on the surface of the aircraft may change with time. If the surface of the aircraft faces the sun, and the space plasma density and energy are very low, the With a lower positive potential; and if the surface of the aircraft is backlit and the density and energy of the space plasma are high, the surface of the satellite may carry a high negative potential. Therefore, the use of low-energy plasma beams will be more effective than the active control of the potential of electron beams and ion beams, and will be able to effectively regulate the potential of the surface of the medium. The Russian Mir space station uses a pulsed plasma source to neutralize the surface charge of the dielectric material in space. It has the characteristics of simple structure, high neutralization efficiency, and stable operation. However, the pulsed plasma source decomposes the surface material of the working medium by high-temperature arc ablation Combined ionization produces plasma, which consumes high energy and consumes solid materials.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for actively controlling the surface potential of dielectric materials in a high vacuum environment. In a high vacuum environment below 10 ^-4 Pa, 2.45 GHz microwaves are fed into the The plasma source body in the vacuum chamber breaks down the working gas in the plasma chamber through the microwave coaxial antenna to form plasma. The ring-shaped permanent magnet steel located in the plasma chamber is used to generate a magnetic field with a strength of 0.0875 Tesla. Under the action of the magnetic field A high-density electron cyclotron resonance plasma is formed, and the formed plasma contains electrons and ions that diffuse through the plasma regulating plate to the environment of the workpiece to be processed, so as to realize the active adjustment of the surface charge of the medium.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for actively controlling the surface potential of a dielectric material in a high vacuum environment, the method includes a discharge process and a power elimination process;

The discharge process is specifically as follows:

The microwave system is powered by the microwave power supply system to generate 2.45GHz electromagnetic waves. The electromagnetic waves are fed through the coaxial waveguide in TEM mode and fed into the microwave coaxial antenna through the microwave transmission system. The lower end of the microwave coaxial antenna is located in the plasma chamber of the plasma source body. The plasma source body is located in a vacuum chamber with a vacuum degree below 10 ^-4 Pa, the microwave coaxial antenna completes the discharge process in the plasma chamber, and completes the discharge process in the vacuum chamber with the help of the plasma source body;

Described power elimination process is specifically as follows:

The microwave coaxial antenna discharges in the plasma chamber, and breaks down the working gas to form plasma. The working gas is sent into the plasma chamber through the gas supply system through the rubber hose and the gas supply pipe. The plasma source is equipped with a ring magnet, and the ring magnet A magnetic field pattern with a strength of 0.0875 Tesla is formed in the plasma discharge area, and the plasma is subjected to Lorentz force on the plane of the vertical magnetic field to perform cyclotron motion. At the position where the magnetic field strength is 0.0875 Tesla, the electron cyclotron frequency The frequency of the right-handed circularly polarized microwave propagating along the magnetic field is equal to 2.45 GHz. The energy absorbed by the electron resonance is greater than the ionization energy of the gas particles and the molecular dissociation energy. The reaction particles form electron cyclotron resonance plasma, which is neutralized by the electrons and ions contained in the plasma and the positive charges and electrons on the dielectric plate.

As a preferred embodiment, the electricity elimination process is carried out in a vacuum environment below 10 ⁻⁴ Pa.

As a preferred embodiment, the gas supply system includes a gas storage system and a gas control system for controlling the pressure and flow of gas entering the plasma chamber, and the gas of the gas storage system is passed into the plasma source body through an inlet pipe. The plasma chamber, the vacuum system includes a vacuum chamber, the vacuum chamber is equipped with a potentiometer for testing the surface potential of the dielectric material, a dielectric material and a dielectric material placement platform to be controlled, and the vacuum degree of the vacuum chamber is 10 ^-4 Below Pa; the plasma generated by the plasma source is introduced into the vacuum chamber and acts on the surface of the dielectric material whose surface potential is to be controlled.

As a preferred embodiment, the plasma source body includes an air inlet pipe, a coaxial microwave antenna, an annular permanent magnet, a magnetic steel fixing sleeve and a plasma regulating plate, and the magnetic steel fixing sleeve is a cylindrical shape with an open lower end Structure, the microwave coaxial antenna and the air intake pipe are inserted into the inner cavity of the magnetic steel fixing sleeve from the closed end, the ring-shaped permanent magnetic steel is fixedly installed inside the magnetic steel fixing sleeve and surrounds the microwave coaxial antenna outside, the The plasma adjusting plate is fixedly installed on the open end of the magnetic steel fixing sleeve, and the annular permanent magnet, the magnetic steel fixing sleeve, the plasma adjusting plate and the microwave coaxial antenna form a plasma chamber.

As a preferred embodiment, the gas inlet pipe is used to pass the working gas into the plasma chamber, the microwave is fed into the plasma chamber through the microwave coaxial antenna, and the ring-shaped permanent magnet steel is used to generate a 0.0875 Tesla magnetic field in the plasma chamber .

As a preferred embodiment, the plasma source body is arranged in the vacuum chamber by means of a remote control rod sealed and penetrated through the vacuum chamber, and the plasma source body is installed at the end of the remote control rod by means of a fixing ring and a plasma source body shell, so The shell of the plasma source body is connected with the remote control rod by means of a fixing ring, the plasma source body is installed at the lower end of the shell of the plasma source body, and the end of the remote control rod facing away from the plasma source body is fixed to the potentiometer Install.

As a preferred embodiment, the microwave power supply system includes a microwave power supply and a magnetron, and microwaves are coupled into the plasma source body through a microwave transmission system, and the microwave transmission system includes a coaxial waveguide, an adjuster, a directional coupler, an air load , a detector, a coaxial cable and a coaxial microwave antenna, the microwave coaxial waveguide is connected to the isolator through a coaxial plug, the isolator is connected to the directional coupler through the coaxial waveguide, and the air load of the detector is installed on the directional coupler Above, the directional coupler is connected to the three-pin adapter used to adjust the impedance matching of the microwave transmission line through the coaxial cable. The axial cable is connected to the microwave coaxial antenna of the plasma source body, and through the microwave coaxial antenna, the working gas is broken down in the plasma chamber to form plasma. The plasma drifts and diffuses into the vacuum chamber through the plasma regulating plate, and acts on the surface to be controlled. potential of the dielectric material surface.

As a preferred embodiment, the working gas of the gas storage system is inert gas, reactive gas or mixed gas; the working gas of the gas storage system is carried by a pressure vessel or compressed by a compressor from the external space.

As a preferred embodiment, the inert gas is one of helium, neon, argon, krypton, xenon, and radon, and the active gas or mixed gas is one of nitrogen, oxygen, air, and hydrogen.

As a preferred embodiment, the microwave system includes a microwave generator and a microwave transmission system for generating 2.45GHz microwaves, the microwave generator is composed of a microwave power supply and a magnetron; the microwave produced by the microwave generator passes through The microwave transmission system is transmitted to the plasma chamber of the plasma source body; the microwave generator is in a continuous working mode or a pulse working mode; in the pulse working mode, its pulse width, duty cycle, and working duration are adjustable.

The beneficial effects of adopting the above technical scheme are: the use of ECR plasma to eliminate the surface charge of the dielectric material avoids the use of a single beam source (ion beam or electron beam) to select the polarity of the surface charge of the dielectric material; the use of ring permanent magnets The size and position of the magnetic field required for steel generation avoids the use of coils and power systems as well as possible water cooling systems, greatly reducing the size and weight of the plasma source body, which is beneficial to use in special environments that need to limit weight; use high flexibility The coaxial waveguide transmission line effectively improves the large-scale operability of the plasma source; the ECR plasma can discharge and work stably under extremely low pressure; the plasma density and plasma electron temperature can be effectively adjusted by using the plasma regulating plate And other parameters, and then effectively regulate the clamping voltage; the temperature of the plasma source used is low, there is no molten material, no pollution, long life, and the surface potential control is more stable and controllable.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Fig. 2 is a partial schematic diagram of the microwave generation and transmission system.

Fig. 3 is a partial schematic diagram of the microwave generation and transmission system.

Fig. 4 is a schematic diagram of the plasma acting on the sample on the surface of the sample stage.

Fig. 5 Schematic diagram of the structure of the microwave ECR plasma source.

Figure 6 Schematic diagram of microwave ECR discharge.

Fig. 7 The magnetic field amplitude and distribution diagram of the annular permanent magnet.

Fig. 8 Simulation results of permanent magnet microwave ECR plasma density.

Fig. 9: Saturated ion current and plasma density variation with microwave current.

Fig. 10 Simulation diagram of the evolution time evolution of positive and negative potentials on the surface of the dielectric plate.

In the attached drawings: 1. Magnetron; 2. The first coaxial waveguide; 3. Isolator; 4. The second coaxial waveguide; 5. Directional coupler; 6. Geophone; 9. Sealed coaxial Connecting end; 10, remote control lever; 11, air load; 12, flexible coaxial cable; 13, three-pin adjuster; 14, rubber tube; 15, vacuum chamber; 16, potentiometer; 17, fixing ring; 18 1. Shell of plasma source body; 19. Plasma source body; 20. Sample; 21. Intake pipe; 22. Microwave coaxial antenna; 24. Annular permanent magnet steel; 25. Magnetic steel fixing sleeve; 27. Plasma chamber ; 28, the plasma adjustment plate; 29, the adjustment hole.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the following description, a lot of specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do it without departing from the meaning of the present invention. By analogy, the present invention is therefore not limited to the specific examples disclosed below.

The invention discloses a method for actively controlling the surface potential of a dielectric material in a high-vacuum environment, including a plasma discharge process and a plasma discharge process. The plasma discharge process generates 2.45 GHz electromagnetic waves by using a microwave power supply to supply power to a magnetron. The electromagnetic wave is fed into the plasma chamber through the coaxial waveguide in the TEM mode, and the transmission passes through the adapter, the circulator and the load. The main function of the adapter is to adjust the impedance matching of the microwave transmission line, and the main function of the circulator is to make the electromagnetic wave one-way transmission , so that the reflected part of the microwave is transmitted to the load port, and the load installed on the load port absorbs all the reflected electromagnetic waves. After passing through the adapter, circulator and waveguide, the electromagnetic wave is fed into the plasma discharge area through the microwave antenna, and the breakdown work The gas forms plasma, and the main function of the ring-shaped permanent magnet steel in the plasma chamber is to form a magnetic field pattern with a strength of 0.0875 Tesla in the plasma discharge area. When doing cyclotron motion, at the position where the magnetic field strength is 0.0875 Tesla, the cyclotron frequency of electrons and the frequency of right-handed circularly polarized microwaves propagating along the magnetic field are both equal to 2.45GHz. After energy, impact ionization, molecular dissociation and particle activation are generated, and plasma discharges and obtains active reaction particles to form electron cyclotron resonance plasma; Charge and electron phase neutralization.

As shown in Figure 1, the gas supply system includes a gas storage system and a gas control system, the gas of the gas storage system passes into the plasma chamber 27 of the plasma source body through rubber hoses, and the gas control system is used to control the gas entering the plasma chamber 27. Gas pressure and flow rate, the plasma generated by the plasma source is introduced into the vacuum chamber 15 with a vacuum degree below 10 ^-4 Pa, and acts on the surface of the material whose surface potential is to be controlled.

Referring to accompanying drawings 4-5, the plasma source body 19 includes an air inlet pipe 21, a microwave coaxial antenna 22, an annular permanent magnet 24, a magnetic steel fixing sleeve 25 and a plasma regulating plate 28, and the magnetic steel fixing sleeve The cylinder 25 is a cylindrical structure with an open lower end. The microwave coaxial antenna 22 and the air intake pipe 21 are inserted into the inner cavity of the magnetic steel fixing sleeve 25 from the closed end. The annular permanent magnetic steel 24 is fixedly installed on the magnetic steel fixing sleeve 25 Inside, and around the outside of the microwave coaxial antenna 22, the inner ring of the annular permanent magnet steel 24 and the microwave coaxial antenna 22 form a plasma chamber 27, and the lower end of the magnetic steel fixing sleeve 25 is fixedly installed with a plasma regulating plate, and the microwave passes through The coaxial antenna 22 is fed into the plasma chamber, and the electrons are accelerated by cyclotron resonance at the 0.0875 Tesla magnetic field generated by the annular permanent magnet steel 24, so that they are stably discharged in a high vacuum. Through the use of ring-shaped permanent magnets and the design of a compact microwave antenna structure, the plasma source body 19 mentioned above has a length of 4 cm, a diameter of about 2.5 cm, a weight of 1 kg, and a discharge power consumption of 20W-100W.

Referring to accompanying drawing 5, described inlet pipe 21 is used for passing in the plasma chamber 27 of working gas, and microwave is fed into plasma chamber 27 through microwave coaxial antenna 22, and annular permanent magnet steel is used in plasma chamber 27 Produces a 0.0875 Tesla magnetic field.

Referring to accompanying drawing 4, described plasma source body is arranged in the vacuum chamber 15 by means of the remote operation lever 10 that seals through vacuum chamber 15, and plasma source body is installed in remote operation by means of fixing ring 17 and plasma source body shell 18. At the end of the rod 10, the plasma source shell 18 is connected with the remote control rod 10 by means of a fixing ring 17. The plasma source body is installed at the lower end of the plasma source body shell 18, and the other side of the remote control rod 10 end is fixed with a potentiometer 16 , the plasma source body shell 18 is used to fix the plasma source body 19, and is fixed on the remote control lever 10 through the fixing ring 17, and the fixing ring 17 fixes the potentiometer 16 on the other side of the plasma source body 19 at the same time for monitoring The surface potential of the sample 20, when the plasma source 19 is fed with microwaves, plasma is generated and diffused to the surface of the sample 20, and the electrons and ions contained in the plasma react with the positive and negative charges attached to the sample surface, Eliminate the surface charge of the sample and reduce its surface potential.

Referring to accompanying drawings 1-2, the microwave power supply system includes a microwave power supply and a magnetron 1, microwaves are coupled into the plasma source body through a microwave transmission system, and the microwave transmission system includes a coaxial waveguide, an adjuster, a directional coupler 5, an air The load 11, the detector 6, the flexible coaxial waveguide and the microwave coaxial antenna 22, the microwave coaxial waveguide is connected to the isolator 3 through the coaxial plug, and the isolator 3 is connected to the directional coupler 5 through the coaxial waveguide, A geophone 6 and an air load 11 are installed on the directional coupler 5, and the directional coupler 5 is connected to a three-pin adapter 13 through a flexible coaxial cable 12, and the three-pin adapter 13 is used to adjust the impedance matching of the microwave transmission line, and the three-pin The adjuster 13 is docked with the vacuum chamber 15 through the sealed coaxial connection end 9, and the output end of the three-pin adjuster 13 is connected to the microwave coaxial antenna 22 of the plasma source body through the radio frequency coaxial cable, and the microwave coaxial antenna 22 is connected to the plasma chamber. 27 breaks down the working gas to form plasma, and the plasma drifts and diffuses to the surface of the dielectric plate through the plasma regulating plate 28 .

Specifically, the first coaxial waveguide 2 connected to the magnetron 1, the coaxial waveguide 2 is connected to the isolator 3 through the coaxial plug, the isolator 3 is connected through the second coaxial waveguide 4, and then the second coaxial waveguide The coaxial waveguide 4 is connected with the directional coupler 5, and the wave detector 6 is installed on the directional coupler 5 to detect the microwave power transmitted in the positive direction in real time, and the air load 11 is installed on the directional coupler 5 to absorb the reflected microwave, so as to protect the magnetron 1 from Destroyed by reflected microwaves, the directional coupler 5 is connected to the three-pin adapter 13 through the flexible coaxial cable 12. The three-pin adapter 13 is mainly used to adjust the impedance of the microwave transmission line to meet the output of the maximum efficiency. The three-pin adapter 13 passes The sealed coaxial connection end 9 is connected to the vacuum chamber 15 of the power dissipation simulation system. The sealed coaxial connection end 9 is mainly used to transmit microwaves into the vacuum chamber while ensuring the vacuum degree of the vacuum chamber. The vacuum chamber 15 has a background vacuum of 10 ^- Below ⁴ Pa, the remote control rod 10 in the vacuum chamber 15 is used to fix the plasma source shell 18 and adjust its position. The vertical part of the remote control rod 10 is sealed by magnetic fluid to ensure the vacuum degree of the vacuum chamber 15. Rotation operation of the remote control lever 10 is permitted.

Fig. 6 shows a schematic diagram of plasma discharge based on the above structure.

Fig. 7 shows the simulation results of the magnitude and position of the magnetic field generated in space by the annular permanent magnet mentioned in the above structure.

FIG. 8 shows the simulation results of the plasma density and distribution generated by the plasma source body 19 with the above structure.

Figure 9 shows the experimental results of saturated ion flow and plasma density analysis obtained by single-probe measurement. The gas flow and corresponding working pressure are 0.1sccm, 0.15sccm, 0.2sccm and 2.6mPa, 2.8mPa, 3.0mPa, respectively. As the microwave current increases from 22mA to 37mA, the plasma density increases from 10 ¹³ m ^-3 to 6×10 ¹³ m ^-3 (taking the electron temperature as 1.25eV).

Figure 10 shows the simulation results of the time evolution of the surface potential of the dielectric plate when the surface density of the attached charge on the surface of the dielectric sample is plus or minus 28.5 μC/ ^m2 . It can be seen that the microwave ECR plasma source based on the above structure can effectively and quickly eliminate the dielectric The positive and negative charges on the surface of the plate, the elimination time of the positive charge (6500V) on the surface of the medium plate is about 1 millisecond, and the elimination time of the negative charge (negative 6500V) on the surface of the medium plate is about 0.25 seconds.

The working principle of the present invention is:

The control method involved in the present invention can be divided into two processes, one is a discharge process, and the other is a power elimination process; the plasma discharge process is to generate 2.45GHz microwaves by using a microwave power supply to supply power to a magnetron. The mode is fed into the plasma chamber through the coaxial waveguide (rectangular waveguide), and the transmission passes through the adjuster (rectangular waveguide three-pin or four-pin, coaxial three-pin, etc.), circulator, load (water load or air load), etc. . The main function of the adjuster is to adjust the impedance matching of microwave transmission lines (including transmission lines and microwave antennas, etc.) to achieve the purpose of optimal microwave input; the main function of the circulator is to make electromagnetic waves transmit in one direction, so that the microwaves in the reflected part will not return The load (water load or air load) installed on the load port will absorb all the reflected electromagnetic waves, thereby protecting the electromagnetic wave generating end. After passing through the three-pin adjuster, circulator, and waveguide (rectangular waveguide or coaxial waveguide), the electromagnetic wave is fed into the plasma discharge area through the microwave antenna, and breaks down the working gas to form plasma. The main function of the ring-shaped permanent magnet steel in the plasma chamber is to form a magnetic field pattern with a strength of 0.0875 Tesla in the plasma discharge area, and the electrons are subjected to the Lorentz force on the plane of the vertical magnetic field to perform cyclotron motion. At the position where the magnetic field strength is 0.0875 Tesla, the electron cyclotron frequency and the right-handed circularly polarized microwave frequency propagating along the magnetic field are both equal to 2.45 GHz, and the electrons will be continuously synchronized and accelerated in the microwave electric field to obtain energy. The energy of the microwave is greater than the ionization energy of the gas particles, the molecular dissociation energy or the excitation energy of a certain state, then it will produce impact ionization, molecular dissociation and particle activation, so as to realize plasma discharge and obtain active reaction particles, forming a high-density electron cyclone Resonant (ECR) plasma. Because electrons can continuously obtain energy from microwave electromagnetic field resonance under the action of a magnetic field, which effectively increases the effective collision cross section of electrons and increases the probability of impact ionization, so high-density ECR plasma can be produced under extremely low pressure (10 ^-4 Below Pa) is produced stably. The working principle of the plasma electricity elimination process is to achieve the purpose of electricity elimination by neutralizing the electrons and ions contained in the plasma with the positive charges and electrons on the dielectric plate. After the ECR plasma is generated, the plasma beam formed is diffused to the environment of the workpiece to be treated through the plasma regulating plate. When the surface of the material carries positive charges, the electrons in the plasma will be charged in the outward direction generated by the positive charges on the surface of the material. The field accelerates and neutralizes the positive charge carried on the surface when it reaches the surface of the material; when the surface of the material carries a negative charge, the positive ions in the plasma will accelerate in the inward direction of the electric field generated by the negative charge on the surface of the material, and the positive ions will When it reaches the surface of the material, it neutralizes the negative charge carried by the surface. Through these two processes, the plasma will be able to effectively eliminate the positive or negative charges on the surface of the dielectric material.

Claims (10)

1. a kind of method of dielectric material surface potential active control under high vacuum environment, it is characterised in that：The described method includes Discharge process and electric eliminating process；

The discharge process is specific as follows：

Powered by microwave power supply system to microwave system and produce 2.45GHz electromagnetic waves, electromagnetic wave passes through on-axis wave in a tem mode Feeding is led, and plasma source body is located at by microwave transmission system feed-in microwave co-axial antenna, microwave co-axial antenna lower end In plasma room, plasma source body is located at vacuum for 10^-4In the vacuum chamber of below Pa, microwave co-axial antenna is in plasma Discharge process is completed in body room, and electric eliminating process is completed in vacuum chamber by means of plasma source body；

The electric eliminating process is specific as follows：

Discharged by microwave co-axial antenna in plasma room, and puncture working gas and form plasma, working gas profit It is sent into air supply system by sebific duct and air supply pipe in plasma room, annular magnetic steel, annular is set in the body of pdp body source Magnet steel forms the magnetic field bit-type that intensity is 0.0875 tesla, plane of the plasma in vertical magnetic field in plasma discharge region On acted on by Lorentz force and do circumnutation, in the position that magnetic field intensity is 0.0875 tesla, electron gyro-frequency and edge The right-handed circular polarization microwave frequency that magnetic field is propagated is equal to 2.45GHz, and the energy that electron resonance absorbs microwave is more than gas particle Ionization energy, ionization by collision, molecular dissociation and particle irradiation are produced after energy of molecular dissociation, plasma discharge simultaneously obtains active anti- Particle is answered, forms Ecr plasma, by electronics included in plasma and ion and dielectric-slab Positive charge and electronics mutually neutralize.

2. dielectric material surface potential Active Control Method under high vacuum environment according to claim 1, it is characterised in that： The electric eliminating process is 10^-4Carried out under the vacuum environment of below Pa.

3. dielectric material surface potential Active Control Method under high vacuum environment according to claim 1, it is characterised in that： The air supply system includes gas storing system and enters plasma chamber for controlling（27）The air pressure of interior gas and flow Gas control system, the gas of the gas storing system pass through air inlet pipe（21）It is passed through the plasma chamber of plasma source body （27）, the vacuum system includes vacuum chamber（15）, the built-in electricity for being useful for tested media material surface current potential of the vacuum chamber Position meter（16）With the dielectric material of surface potential to be controlled（20）And dielectric material placement platform, its vacuum of vacuum chamber is 10^{- 4}Below Pa；The plasma source body（19）Its plasma produced imports vacuum chamber（15）It is interior, and act on tabulation to be controlled The dielectric material surface of face current potential.

4. dielectric material surface potential Active Control Method under high vacuum environment according to claim 1, it is characterised in that： The plasma source body（19）Including air inlet pipe（21）, coaxial microwave antenna（22）, annular permanent magnet steel（24）, magnet steel fixing sleeve Cylinder（25）And plasma adjustable plate（28）, the magnet steel fixes sleeve（25）The tubular structure opened for lower end, microwave are same Axis antenna（22）And air inlet pipe（21）From magnet steel fixes sleeve（25）Blind end be inserted into its inner cavity, the annular permanent magnet steel（24） It is fixedly mounted on magnet steel fixes sleeve（25）Inner side, and it is centered around microwave co-axial antenna（22）Outside, the in vitro adjustable plate of grade （28）It is fixedly mounted on magnet steel fixes sleeve（25）Open end, the annular permanent magnet steel（24）, magnet steel fixes sleeve（25）, etc. Gas ions adjustable plate（28）With microwave co-axial antenna（22）Form plasma chamber（27）.

5. dielectric material surface potential Active Control Method under high vacuum environment according to claim 3, it is characterised in that： The air inlet pipe（21）For working gas to be passed through plasma chamber（27）Interior, microwave passes through microwave co-axial antenna（22）Feed-in Plasma chamber（27）, annular permanent-magnet steel is in plasma chamber（27）0.0875 Tesla magnetic fields of interior generation.

6. dielectric material surface potential Active Control Method under high vacuum environment according to claim 4, it is characterised in that： The plasma source body（19）Run through vacuum chamber by means of sealing（15）Remote operating bar（10）Arranged on vacuum chamber（15）It is interior, etc. Plasma source body（19）By means of retainer ring（17）With plasma source body case（18）Installed in remote operating bar（10）End, institute State plasma source body case（18）By means of retainer ring（17）With remote operating bar（10）Connection, the plasma source body are installed on Plasma source body case（18）Lower end, the remote operating bar（10）It deviates from plasma source body（19）A side end with electricity Position meter（16）It is fixedly mounted.

7. dielectric material surface potential Active Control Method under high vacuum environment according to claim 1, it is characterised in that： The microwave power supply system includes microwave power supply and magnetron（1）, microwave is coupled into plasma by microwave transmission system Source body, the microwave transmission system include coaxial waveguide, tuner, directional coupler（5）, air load（11）, wave detector （6）, coaxial cable（12）With coaxial microwave antenna（22）, the microwave coaxial waveguide passes through coaxial plug and isolator（3）Even Connect, isolator（3）Pass through coaxial waveguide and directional coupler（5）Connection, wave detector（6）Air load（11）Installed in orientation Coupler（5）On, directional coupler（5）Pass through coaxial cable（12）With three of the impedance matching for adjusting microwave transmission circuit Pin tuner（13）Connection, three pin tuners（13）By sealing coaxially connected end（9）With vacuum chamber（15）Docking, three pins Follow closely tuner（13）Its output terminal connects the microwave co-axial antenna of plasma source body by coaxial cable（22）, and pass through microwave Coaxial antenna（22）In plasma chamber（27）Interior breakdown working gas forms plasma, and plasma passes through plasma tune Save plate（28）Driftdiffusion acts on the dielectric material surface of surface potential to be controlled to vacuum chamber（20）.

8. dielectric material surface potential active control system under high vacuum environment according to claim 1, it is characterised in that： Its working gas of the gas storing system is inert gas, active gases or mixed gas；The gas storing system Its working gas is carried by pressure vessel or compressor is obtained from exterior space compression.

9. dielectric material surface potential active control system under high vacuum environment according to claim 8, it is characterised in that： The inert gas is helium, one kind in neon, argon, krypton, xenon, radon, the active gases or mixed gas are nitrogen, oxygen, sky One kind in gas, hydrogen.

10. dielectric material surface potential active control system under high vacuum environment according to claim 1, its feature exist In：The microwave system includes being used for the microwave generator and microwave transmission system for producing 2.45GHz microwaves, and the microwave occurs Device is made of microwave power supply and magnetron；Its microwave for producing of the microwave generator by microwave transmission system be transmitted to etc. from Daughter source body（19）Plasma chamber（27）It is interior；The microwave generator is continuous operation mode or pulse working mode； Its pulsewidth, duty cycle, run duration are adjustable under the pulse working mode.