CN103245655A - Experimental apparatus for acquiring large-area uniform discharge plasmas - Google Patents

Abstract

An experimental device for obtaining large-area uniform discharge plasma belongs to the field of plasma technology, and is composed of a bipolar nanosecond pulse power supply, a reactor, a multi-pin-plate electrode, a gas distribution system, a spectral measurement system and a discharge measurement system; The bipolar nanosecond narrow pulse power supply drives the dielectric barrier discharge of air and other mixed gases between the multi-needle-plate electrodes installed in the reactor, and the mixed gases are input into the reactor through the gas distribution system. The spectral measurement system collects the photon information of the plasma discharge in real time and inputs it to the computer for spectral analysis. The discharge measurement system collects the discharge voltage and current of the high-voltage nanosecond pulse power supply in real time, and displays them on a digital oscilloscope. The invention adopts a bipolar nanosecond narrow pulse power supply to generate large-area discharge plasma without the action of a magnetic field; the generated plasma is uniform and dispersed; the generated plasma has high electron density and high energy utilization rate , Low energy consumption, easy to control the discharge process.

Description

An Experimental Device for Obtaining Large-area Uniform Discharge Plasma

technical field

The invention belongs to the field of plasma technology, and in particular relates to a dielectric barrier discharge plasma technology which is driven by a bipolar nanosecond pulse power supply under a multi-needle-plate electrode structure and obtains large-area low-temperature and uniform dielectric barrier discharge in air and mixed gases .

technical background

Traditionally, dielectric barrier discharge plasma is driven by AC power. Under the drive of AC power, the conditions for uniform and diffuse discharge of dielectric barrier discharge plasma in atmospheric pressure air are very harsh, and it is easy to convert into discharge modes such as sparks and arcs, and the gas High temperature, low energy utilization rate, serious damage to the material surface, high operating cost, etc., these shortcomings of discharge greatly restrict its industrial application, seriously affecting its industrial application.

In the nanosecond pulse discharge, because the nanosecond pulse has the characteristics of a steep pulse voltage rising edge and a short pulse duration, the electrons are accelerated to the greatest extent in the rapidly rising electric field, so the power of the electrons in the nanosecond pulse discharge There is a big difference between the physical characteristics and the traditional AC discharge. Under the same conditions, nanosecond pulse discharge can obtain higher electron temperature and energy utilization efficiency. At the same time, the shorter single pulse duration can make the discharge extinguish in time during the transition to the local thermodynamic equilibrium state, which is beneficial to control the stability and non-thermodynamic equilibrium of the discharge, and it is easier to achieve stable and uniform discharge in atmospheric pressure air. , Therefore, the nanosecond pulse discharge plasma has the advantages of high density of high-energy electrons, high average electron energy, generation of chemically active particles and high efficiency of VUV generation. At the same time, the multi-needle-plate electrode structure can generate large-area discharge plasma. By combining the advantages of nanosecond pulse discharge and multi-needle-plate electrode structure, a large area of uniform low-temperature discharge plasma can be generated under atmospheric pressure. It is used in food Processing, material surface treatment, thin film deposition, microbial mutagenesis, drinking water sterilization, removal of toxic and harmful gases, etc. have important application prospects, and are highly valued by laboratories at home and abroad. Under the multi-needle-plate electrode structure, using bipolar nanosecond pulse power supply to drive dielectric barrier discharge can obtain a large area of uniform discharge low-temperature discharge plasma in air and other mixed gases, which can be used in material surface treatment, film deposition, microbial induction Transformation, drinking water sterilization and other fields have important commercial value and broad industrial application prospects.

Patent CN1927408A solves the problem of removing harmful gases by using dielectric barrier discharge plasma generated by unipolar nanosecond pulse power supply on the basis of introducing parallel magnetic fields, and greatly improving the purification efficiency. However, there are problems that (1) the generated plasma is a filamentous discharge; (2) there is no specific introduction to the diagnostic method of the plasma characteristics; (3) the discharge plasma generated without the action of an external magnetic field is not introduced. Patents CN1559651A and CN2500026Y solve the problem of purifying harmful gases with plasma generated by pulsed corona discharge, but the existing problem is that corona discharge only occurs near the sharp electrodes, and a strong electric field is generated only in a very thin corona layer, resulting in The average electron energy is about 3 eV. Due to its low average electron energy, small discharge plasma volume, weak discharge intensity and low electron density, the number of active particles and free radicals generated in the discharge space is small, and the effective treatment space Therefore, these seriously affect the purification efficiency of plasma to harmful gases, and also greatly limit the practical application range of plasma.

Contents of the invention

In order to solve the problems of small discharge plasma area, uneven discharge, low energy utilization rate and lack of real-time diagnosis of discharge plasma characteristics, the present invention provides an experimental device for obtaining large-area uniform discharge plasma. It consists of a second pulse power supply, a reactor, a multi-needle-plate electrode, a gas distribution system, a spectral measurement system and a discharge measurement system.

The bipolar nanosecond pulse power supply can alternately generate the same narrow pulse voltage waveform in the positive and negative directions; the pulse rise time is about 20 ns, the pulse width is about 60 ns, the pulse peak voltage is 0-60kV, and the pulse repetition frequency is 0-400Hz Continuously adjustable within the range.

The multi-needle-plate electrode is composed of upper electrode, multi-needle electrode, plate electrode, lower electrode and dielectric sheet; the upper electrode, multi-needle electrode, plate electrode and lower electrode are all made of stainless steel; the plate electrode is horizontally fixed, and It is connected with the lower electrode; the lower electrode is firmly grounded through the wire; the dielectric sheet covers the upper surface of the plate electrode; the multi-needle electrode is fixed under the upper electrode, and the needle tip is facing downward; the multi-needle electrode is opposite to the dielectric sheet to form a discharge gap; The gap between the tip of the needle electrode and the dielectric sheet is adjustable in the range of 0-30 mm; the other end of the upper electrode is connected to the output end of the bipolar nanosecond pulse power supply.

The reactor is a sealed cylindrical container with an insulating material on the upper surface and stainless steel on the four sides and the bottom surface. The multi-needle-plate electrode is placed in the center of the reactor, and the upper electrode passes through the insulating top surface of the reactor and the bipolar The output end of the nanosecond pulse power supply is connected; the lower electrode passes through the lower bottom of the reactor and is firmly grounded; there is a circular flat quartz window for observing the discharge at the same elevation as the side of the reactor and the discharge gap. The tightness is very good, and except for the quartz window, all the inner walls are uniformly blackened to prevent the influence of stray light on the spectral measurement; the side wall of the reactor is equipped with an inlet pipe and an outlet pipe with an air valve.

The gas distribution system sends the used gas into the discharge gap in the reactor through the inlet pipeline; the excess gas is discharged through the gas outlet pipeline of the gas distribution system.

The spectral measurement system collects the photon information of the plasma discharge between the multi-needle-plate electrodes in real time through the quartz window installed in the reactor, and converts the optical information into digital information and inputs it to the computer for spectral analysis.

The discharge measurement system collects the discharge voltage and current of the bipolar nanosecond pulse power supply in real time and displays them on a digital oscilloscope.

The bipolar nanosecond pulse power supply, spectrum measurement system and discharge measurement system all need to be shielded with electromagnetic shielding covers, and all electromagnetic shielding covers are firmly grounded.

The gas distribution system consists of a mass flow control meter, an air inlet pipeline, an air outlet pipeline, an air valve and a plurality of gas cylinders; multiple gas cylinders with air valves are connected to the mass flow controller, and the inlet with air valves One end of the gas pipeline communicates with the mass flow control meter, and the other end penetrates into the reactor to reach the multi-needle electrode of the multi-needle-plate electrode and the edge between the dielectric sheet to form a gas injection port; the gas outlet pipeline with the gas valve is arranged at the same Above the reactor on the opposite side of the inlet line.

The discharge measurement system consists of a digital oscilloscope, a voltage probe line and a current probe line; connect one end of the voltage probe line to the upper electrode and the other end to the digital oscilloscope; connect one end of the current probe line to the wire between the lower electrode and ground , and the other end is connected to the digital oscilloscope.

The spectral measurement system consists of lenses, fiber optic probes, optical fibers, high-resolution grating monochromators, charge-coupled devices, and computers; the lens is fixed on the bracket outside the quartz window of the reactor, and the fiber optic probe is fixed on the other side of the lens for three-dimensional displacement On the platform, make it face the discharge gap, and adjust the center point of the lens and the position of the fiber optic probe at the same time, so that the needle tip of the middle needle of the multi-needle electrode, the center point of the lens, and the fiber optic probe are on the same horizontal line; The converged optical signal is transmitted to a high-resolution grating monochromator through an optical fiber for light splitting. The split monochromatic light signal is converted into a digital signal by a charge-coupled device, and finally collected and processed by a computer.

In the multi-needle-plate electrode, the number of needle electrodes in the multi-needle electrode can be increased or decreased according to actual needs to form an electrode pattern of any shape, and the distance between the needles can also be adjusted.

The dielectric sheet can be any one of quartz, ceramics, or polytetrafluoroethylene.

The multi-needle electrodes can not only adjust the same distance between all the needle electrodes and the lower electrode, but also keep different distances between different needle electrodes and the lower electrode.

There can be 1 to 4 observation windows of the reactor.

The beneficial effects of the present invention are: (1) using bipolar nanosecond pulse power supply, a large area of discharge plasma is generated without the action of an external magnetic field; (2) the generated plasma is uniform and dispersed; (3) ) The electron density in the plasma generated is high, the energy utilization rate is high, the energy consumption is low, and the discharge process is easy to control. (4) The characteristics of uniform plasma can be diagnosed by high-resolution grating monochromator and digital oscilloscope, so as to be better applied in actual industry.

Description of drawings

Fig. 1 is a schematic diagram of the present invention.

Figure 2 is a distribution diagram of multi-needle electrode needles, which consist of 13 needles forming two patterns of seven-star and hexagonal structures.

In the figure: 1. Bipolar nanosecond pulse power supply; 2. Upper electrode; 3. Voltage probe circuit; 4. Digital oscilloscope; 5. Mass flow controller; 6. Intake pipeline; 7. Air valve; 8. Gas bottle; 9. reactor; 10. multi-needle electrode; 11. outlet line; 12. plate electrode; 13. dielectric sheet; 14. lens; 15. optical fiber probe; 16. lower electrode; 17. current probe line; . Optical fiber; 19. Computer; 20. High-resolution grating monochromator; 21. Charge-coupled device; 22. Electromagnetic shielding cover.

specific implementation plan

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

An experimental device for obtaining large-area uniform discharge plasma is composed of a bipolar nanosecond pulse power supply 1, a reactor 9, a multi-needle-plate electrode, a gas distribution system, a spectral measurement system and a discharge measurement system.

Bipolar nanosecond pulse power supply 1 can alternately generate the same narrow pulse voltage waveform in positive and negative directions; the pulse rise time is about 20 ns, the pulse width is about 60 ns, the pulse peak voltage is 0-60kV, and the pulse repetition frequency is 0- Continuously adjustable in the range of 400Hz.

The multi-needle-plate electrode is composed of upper electrode 2, multi-needle electrode 10, plate electrode 12, lower electrode 16 and dielectric sheet 13; upper electrode 2, multi-needle electrode 10, plate electrode 12 and lower electrode 16 are all made of stainless steel The plate electrode 12 is in a horizontal fixed state and is connected to the lower electrode 16; the lower electrode 16 is firmly grounded through a wire; the dielectric sheet 13 is covered on the upper surface of the plate electrode 12; Down; the multi-needle electrode 10 is opposite to the dielectric sheet 13 to form a discharge gap; the gap between the tip of the multi-needle electrode 10 and the dielectric sheet 13 is adjustable in the range of 0-30 mm; the other end of the upper electrode 2 is connected to the bipolar nanosecond The output terminal of the pulse power supply 1 is connected. The needle tip of the multi-needle electrode 10 is rounded, the diameter of the needle tip is about 0.8 mm, and the distance between the needles is 10 mm; the plate electrode 12 is a stainless steel disc with a diameter of 80 mm, and the surface of the stainless steel disc is covered with a dielectric sheet 13 It has a thickness of 1 mm and a diameter of 100 mm.

The reactor 9 is an insulating material on the upper surface, and a sealed cylindrical container made of stainless steel on the four sides and the bottom surface. The multi-pin-plate electrode is placed in the center of the reactor 9, and the upper electrode 2 passes through the insulating top of the reactor 9. The surface is connected to the output end of the bipolar nanosecond pulse power supply 1; the lower electrode 16 passes through the lower bottom surface of the reactor 9 and is firmly grounded; the side of the reactor 9 and the discharge gap are at the same elevation for observation. Flat quartz window, the entire reactor 9 has good airtightness, and except for the quartz window, all inner walls are evenly painted black to prevent stray light from affecting the spectral measurement; the side wall of the reactor 9 is equipped with an inlet pipeline 6 and an outlet pipeline 11.

The gas distribution system feeds the used gas into the discharge gap in the reactor 9 through the inlet pipeline 6; the excess gas is discharged through the gas outlet pipeline 11 of the gas distribution system.

The spectral measurement system collects the photon information of the plasma discharge between the multi-needle-plate electrodes in real time through the quartz window installed in the reactor, and converts the optical information into digital information and inputs it to the computer 19 for spectral analysis.

The discharge measurement system collects the discharge voltage and current of the bipolar nanosecond pulse power supply 1 in real time and displays them on the digital oscilloscope 4 .

The bipolar nanosecond pulse power supply 1, the spectrum measurement system and the discharge measurement system all need to be shielded with electromagnetic shielding covers 22, and the shells of all electromagnetic shielding covers 22 are firmly grounded.

The gas distribution system is composed of a mass flow controller 5, an air inlet pipeline 6, an outlet pipeline 11, an air valve 7 and a plurality of gas cylinders 8; multiple gas cylinders 8 with an air valve 7 are connected to the mass flow controller 5 Among them, one end of the air inlet pipeline 6 with the gas valve 7 communicates with the mass flow control meter 5, and the other end penetrates into the reactor 9 to reach the edge between the multi-needle electrode 10 and the dielectric sheet 13 of the multi-needle-plate electrode. Gas injection port; the outlet pipeline 11 with the gas valve 7 is placed above the reactor 9 on the side opposite to the inlet pipeline. The gas in the gas cylinder 8 can be N ₂ gas, He gas, O ₂ gas and Ar gas; the gas distribution system utilizes the mass flow controller 5 to measure the gas flow, and the used gas enters the reactor by mixing as a working gas, and then passes through A gas jet evenly enters the discharge gap, and the gas flow rate remains constant at 200 ml/min throughout the experiment, and the gas valve 7 controls the introduction of gas. The _N2 gas, He gas, O _gas2 and Ar gas used in the experiment The concentration is 99.999% high-purity gas. The air valve at the air outlet pipeline 11 is in an open state. If the working gas is air, the experiment can be carried out directly in the air without the above gas distribution operation.

The discharge measurement system consists of a digital oscilloscope 4, a voltage probe line 3 and a current probe line 17; one end of the voltage probe line 3 is connected to the upper electrode 2, and the other end is connected to the digital oscilloscope 4; one end of the current probe line 17 is connected to the lower electrode 16 and the ground wire, and the other end is connected to the digital oscilloscope 4. What the present invention adopts is that the digital oscilloscope model produced by U.S. Tektronix Company is TDS3052B; Voltage probe circuit P6015A, 1000×3.0pF, 100MΩ, 1:1000, and current probe circuit TCP312.

Spectral measurement system is made up of lens (14), optical fiber probe (15), optical fiber 18, high-resolution grating monochromator 20, charge-coupled device 21 and computer 19; Lens 14 is fixed on the support outside the quartz window of reactor 9 , the fiber optic probe 15 is fixed on the three-dimensional displacement platform on the other side of the lens 14, making it face the discharge gap, and at the same time adjust the center point of the lens 14 and the position of the fiber optic probe 15, so that the needle tip of the middle needle of the multi-needle electrode 10 and the center of the lens 14 point and the optical fiber probe 15 are on the same horizontal straight line; the optical fiber probe 15 collects the light signal converged by the lens 14, and transmits it to the high-resolution grating monochromator 20 through the optical fiber 18 for light splitting, and the monochromatic light signal after the light splitting It is converted into a digital signal by the charge-coupled device 21, and finally collected and processed by the computer 19. The diameter of the lens 14 is 50 mm, and the focal length is 100 mm. The high-resolution grating monochromator model is: Andor SR-750i. The grating has 2400 lines/mm, and its blazed wavelength is 300 nm. There are a large number of excited-state particles in the plasma, and the excited-state particles will emit photons during the de-excitation process. The energy of the photons is related to the type of the particle and the energy level involved. By detecting the spectrum of these photons, it can be judged The species of matter present in a plasma and the state it is in.

The number of needle electrodes of the multi-needle electrode 10 in the multi-needle-plate electrode can be increased or decreased according to actual needs to form an electrode pattern of any shape, and the distance between the needles can also be adjusted.

The dielectric sheet 13 can be any one of quartz, ceramics, or polytetrafluoroethylene.

The multi-needle electrode 10 can not only adjust all the needle electrodes to maintain the same distance from the lower electrode, but also can maintain different distances between different needle electrodes and the lower electrode.

There can be 1 to 4 observation windows installed on the side wall of the reactor 9.

The bipolar nanosecond pulse power supply 1, the spectrum measurement system and the discharge measurement system all need to be shielded with electromagnetic shielding covers 22, and the shells of all electromagnetic shielding covers 22 are firmly grounded.

A method of using an experimental device for obtaining large-area uniform discharge plasma provided by the present invention is as follows:

Step 1: Before feeding the test gas, first check the airtightness of the gas path, and then vacuumize the reactor 9 with a mechanical pump. Then use the mass flow controller 5 to measure the flow of different gases from different gas cylinders 8, mix the mixed gases of different concentrations required by the proportioning experiment, and input the mixed gas into the reactor 9 through the air inlet line 6 and then pass through the gas injection port evenly Pass the mixed gas into the discharge gap. The flow rate of the mixed gas remains constant at 200 ml/min throughout the experiment. If the working gas is air, the experiment can be carried out directly in the air without the above steps of gas distribution.

Step 2: After checking that the circuit is correct, turn on the digital oscilloscope 4, the high-resolution grating monochromator 20 and the computer 19, adjust the voltage and current of the digital oscilloscope 4 to the maximum range; The rate grating monochromator 20 is adjusted to the third grating, that is, the grating is 2400 lines/mm, and the blaze wavelength is 300 nm, and the gratings of 500 lines/mm and 1200 lines/mm can also be selected according to needs. The exposure time is 1 s, and the measurement range is 200-900 nm. After debugging, check whether the instrument works normally, and use light-shielding materials to cover the windows of other reactors 9 that do not need to be observed.

Step 3: After the instrument is checked to be normal, turn on the bipolar nanosecond pulse power supply 1, first set the pulse repetition frequency to 150Hz, and then adjust the pulse peak voltage to 30 kV. Specifically, the power supply parameters can be adjusted according to actual needs. Plasma discharge Initially, a large area of uniform plasma is generated between the multi-needle electrode 10 and the dielectric sheet 13 . Then, the current and voltage waveform diagram of the discharge plasma and the emission spectrum of the plasma are respectively recorded by the digital oscilloscope 4 and the computer 19 . After the recording is completed, adjust the pulse peak voltage and pulse repetition frequency to 0, turn off the bipolar nanosecond pulse power supply 1, and the discharge ends.

Step 4: Analyzing the current and voltage waveform diagram and emission spectrum of the discharge plasma by computer 19, the plasma power, power density, energy consumption, electron density, rotation temperature, vibration temperature, electron temperature and active particle components produced by the discharge can be obtained and concentration and other important parameters. These parameters can intuitively reflect some important characteristics of the generated plasma. You can also take photos of the discharge with a Canon 550D digital camera, and you can intuitively judge the area of the discharge plasma and the uniformity of the discharge from the photos.

Claims (9)

1. an experimental provision that obtains the even discharge plasma of large tracts of land is made up of bipolarity nanosecond pulse power supply (1), reactor (9), spininess-board-like electrode, gas distributing system, spectral measurement system and discharge measuring system; Bipolarity nanosecond pulse power supply (1) can be submitted for producing identical burst pulse voltage waveform in positive negative direction; Be about 20 ns pulse rise time, pulsewidth is about 60 ns, and peak impulse voltage 0-60 kV is adjustable continuously in the pulse repetition rate 0-400Hz scope; It is characterized in that:

Spininess-board-like electrode is made up of top electrode (2), multistylus electrode (10), plate electrode (12), bottom electrode (16) and dieelctric sheet (13); Top electrode (2), multistylus electrode (10), plate electrode (12) and bottom electrode (16) are all made by stainless steel material; Plate electrode (12) is the horizontal fixed state, and links to each other with bottom electrode (16); Bottom electrode (16) is by the lead dead earthing; Dieelctric sheet (13) covers the upper surface of plate electrode (12); Multistylus electrode (10) is fixed on the below of top electrode, and needle point down; Multistylus electrode (10) is relative with dieelctric sheet (13), forms discharging gap; The needle point of multistylus electrode (10) is adjustable in 0-30 mm scope apart from the gap of dieelctric sheet (13); The other end of top electrode (2) is connected with the output terminal of bipolarity nanosecond pulse power supply (1);

Reactor (9) is that a last end face is insulating material, be the hydrostatic column of the stainless steel sealing of making all around with the bottom surface, spininess-board-like electrode places the central authorities of reactor (9), and the insulation end face that top electrode (2) passes reactor (9) is connected with the output terminal of bipolarity nanosecond pulse power supply (1); Bottom electrode (16) passes the bottom surface of reactor (9), and dead earthing; The four direction of reactor (9) side has can be for the circular zero diopter quartz window of observing, and whole reactor (9) impermeability is fine, and except quartz window, the even blacking of all inwalls is to prevent that parasitic light is to the influence of spectral measurement; The sidewall of reactor (9) is equipped with air inlet pipeline (6) and the outlet pipe (11) that has air valve;

Gas distributing system is with the gases used discharging gap that passes through in air inlet pipeline (6) input reactor (9); Unnecessary gas is discharged by the outlet pipe (11) of gas distributing system;

Spectral measurement system, the photon information of plasma discharge between real-time collecting spininess-board-like electrode, and optical information is changed into numerical information be input to computing machine and carry out spectral analysis;

The discharge measuring system, sparking voltage and the electric current of real-time collecting bipolarity nanosecond pulse power supply (1), and shown by digital oscilloscope (4);

Bipolarity nanosecond pulse power supply (1), spectral measurement system and discharge measuring system all need use electro-magnetic shielding cover (22) shielding, all electro-magnetic shielding covers (22) shell dead earthing.

2. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1, it is characterized in that gas distributing system is made up of mass rate control meter (5), air inlet pipeline (6), outlet pipe (11), air valve (7) and a plurality of gas cylinder (8); A plurality of gas cylinders (8) that have air valve (7) are communicated in the mass rate control meter (5), air inlet pipeline (6) one ends that have air valve (7) are communicated with mass rate control meter (5), and the other end penetrates the multistylus electrode (10) and the edge between the dieelctric sheet (13) that arrive spininess-plate electrode in the reactor (9) and forms puff prot; The outlet pipe (11) that has air valve (7) is placed in the top with the reactor (9) of air inlet pipeline opposite side.

3. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1 is characterized in that, the discharge measuring system is made up of digital oscilloscope (4), voltage probe circuit circuit (3) and current probe circuit circuit (17); Voltage probe circuit (3) one ends are connected on the top electrode (2), and the other end is connected on the digital oscilloscope (4); Current probe circuit (17) one is terminated on the lead between bottom electrode (16) and the ground connection, and the other end is connected on the digital oscilloscope (4).

4. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1, it is characterized in that spectral measurement system is made up of lens (14), fibre-optical probe (15), optical fiber (18), high-resolution gration monochromator (20), charge-coupled image sensor (21) and computing machine (19); Lens (14) are fixed on the support in the quartz window outside of reactor (9), fibre-optical probe (15) is fixed on the three-D displacement platform of lens (14) opposite side, make it over against discharging gap, regulate the position of lens (14) central point and fibre-optical probe (15) simultaneously, make needle point, lens (14) central point and fibre-optical probe (15) three of multistylus electrode (10) middle needle on same horizontal linear; Fibre-optical probe (15) is collected by the light signal after lens (14) convergence, and transfer to high-resolution gration monochromator (20) through optical fiber (18) and carry out light splitting, monochromatic light signal after the light splitting changes digital signal into through charge-coupled image sensor (21), at last by computing machine (19) acquisition process.

5. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1, it is characterized in that, the pin electrode number of multistylus electrode (10) can increase or reduce the pattern of the electrode of forming arbitrary shape according to the demand of reality in spininess-board-like electrode, but the distance between metering needle and the pin also simultaneously.

6. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1 is characterized in that the needle tip of multistylus electrode (10) by rounding, and the needle point diameter is about 0.8 mm, and the distance between pin and the pin is 10 mm; Plate electrode (12) is that diameter is the stainless steel disk of 80 mm, and its thickness of stainless steel disc surfaces overwrite media sheet (13) is 1 mm, and diameter is 100 mm.

7. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1 or 5 is characterized in that, dieelctric sheet (13) can be any one of quartzy, pottery or teflon.

8. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 1, it is characterized in that multistylus electrode (10) not only can be regulated all pin electrodes distance identical with the bottom electrode maintenance simultaneously can also the differing needles electrode distance different with the bottom electrode maintenance.

9. a kind of experimental provision that obtains the even discharge plasma of large tracts of land according to claim 3 is characterized in that, the diameter of lens (14) is 50 mm, and focal length is 100 mm.

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