Self-organizing multilayer discharge plasma generation device and method

Abstract

The application belongs to the technical field of discharge plasma equipment, and particularly relates to a self-organizing multi-layer discharge plasma generating device and method. The device comprises a vacuum cavity, two electrode connectors fixedly arranged on the cavity wall of the vacuum cavity through high-pressure flanges, a guide rail arranged in the vacuum cavity, two sliding support bodies arranged on the guide rail, one insulating rod arranged on each sliding support body, one electrode arranged on each insulating rod, and the tips of the two electrodes oppositely arranged to form a discharge body. The electrode connectors are connected with the electrodes and a high-voltage power supply through wires. One sliding support body is fixedly connected with one end of an electrode transmission rod, one end of the electrode transmission rod penetrates through the cavity wall of the vacuum cavity and is connected with an adjuster fixedly arranged on the cavity wall of the vacuum cavity, the adjuster is used to push the electrode transmission rod, and then drive one insulating rod to slide along the guide rail to adjust the distance between the two copper electrodes. The application can realize plasma discharge under high pressure and can be controllably eliminated.

Description

Technical Field

[0001] This invention belongs to the technical field of discharge plasma equipment, specifically relating to a self-organized multilayer discharge plasma generation device and method. Background Technology

[0002] Glow discharge plasma is a typical low-temperature plasma rich in active particles such as high-energy electrons, ions, and excited-state atoms, and has wide applications in various cutting-edge scientific fields such as materials processing, thermonuclear fusion, semiconductor industry, and aerospace. Typically, under electric field excitation, the glow discharge generated between electrodes exhibits a continuous and uniform plasma; under specific parameters, this continuous and uniform plasma can spontaneously organize into a multilayered plasma with alternating bright and dark phases. This multilayered discharge plasma, similar to the channel contraction effect of glow discharge, physically involves the ionization instability of the plasma. This instability is generally considered undesirable because it interferes with the uniformity of the plasma column. For example, for light-emitting lamps, this means lamp failure (Levko D, 2021 Physics of Plasmas 28013506); for plasma etching in the microelectronics industry, it affects the uniformity of the plasma, which in turn affects key process parameters such as electron energy distribution function and particle flux (Liu YX, et al., Physical Review Letters, 116, 1–6); in particular, for high-power gas lasers used in the military, this instability directly affects the pumping process, thereby affecting the performance of the laser (Daniel J. Emmons II 2017 Ph.D. Dissertation, Department of the Air Force Institute of Technology, Ohio, pp. 23-24). Currently, the generation of such self-organized multilayer discharge plasma is mostly achieved through radio frequency / direct current discharge at low pressures (Pa levels). For example, Chinese Patent Publication No. CN106470522B (Li Weizhi, et al.) discloses a plasma device with adaptive radio frequency discharge stripes. This device is a typical example of generating glow discharge by applying a radio frequency electric field to the electrodes to produce gas discharge. Another typical glow discharge plasma is generated in a closed direct current discharge tube. For instance, VA Lisovskiy (Eur. J. Phys., 2012, 33: 1537-1545) reported a method for generating multilayer discharge plasma by direct current discharge in a discharge pressure range of 0.1–100 Torr. The multilayer discharge plasma generated in this discharge tube is closely related to the diffusion of electrons within the confined tube wall. In addition, OUYANG Ji-Ting (Chin.Phys.Lett.,2005,22:2892-2894) reported that multilayer discharge plasma also appears in plasma display panels, and the formation of multilayer discharge plasma is related to the distortion of the electric field.

[0003] However, the discharge plasma in existing technologies is generated under low-pressure conditions, and its elimination is uncontrollable. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the prior art, and the technical problem to be solved is: to provide a self-organized multilayer discharge plasma generation device and method to generate discharge plasma under high pressure and to achieve controllable elimination of discharge plasma.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a self-organized multilayer discharge plasma generating device, comprising: a vacuum chamber, wherein two electrode connectors are fixedly mounted on the cavity wall of the vacuum chamber via a high-voltage flange; a guide rail is provided inside the vacuum chamber, and two sliding supports are provided on the guide rail; each sliding support is provided with an insulating rod, and each insulating rod is provided with an electrode; the tips of the two electrodes are arranged opposite each other to form a discharge body; the electrode connectors are connected to the electrodes and a high-voltage power supply via wires; one of the sliding supports is fixedly connected to one end of an electrode transmission rod, and the other end of the electrode transmission rod passes through the cavity wall of the vacuum chamber and is connected to an adjuster; the adjuster is fixedly mounted on the cavity wall outside the vacuum chamber and is used to push the electrode transmission rod, thereby causing one of the insulating rods to slide along the guide rail to adjust the distance between the two electrodes;

[0006] The vacuum chamber is equipped with a vacuum valve and a gas filling valve on its wall. The vacuum valve is connected to a vacuum pump, and the gas filling valve is used to inject gas into the chamber.

[0007] The self-organized multilayer discharge plasma generating device further includes a hollow cylinder, the bottom of which is fixedly connected to the insulating rod, and an electrode hole is provided in the center, with the electrode horizontally disposed in the electrode hole.

[0008] The regulator is a micrometer.

[0009] The insulating rod is made of polytetrafluoroethylene, the sliding support and guide rail are made of stainless steel, the vacuum chamber is made of stainless steel, and an upper flange is provided on its top. The upper flange has handles on its left and right ends and an observation window in its center. The electrode is a copper electrode.

[0010] The self-organized multilayer discharge plasma generation device, wherein the high-voltage power supply is used to generate a voltage with a frequency of 5 to 20 kHz.

[0011] The vacuum chamber is also equipped with a vent valve and a vacuum measuring gauge on its wall. The vent valve is used to release gas to control the gas pressure in the vacuum chamber, and the vacuum measuring gauge is used to measure the vacuum level in the vacuum chamber.

[0012] Furthermore, the present invention also provides a method for generating self-organized multilayer discharge plasma, which is implemented using the self-organized multilayer discharge plasma generating device described in the claims, and includes the following steps:

[0013] Step 1: Adjust the electrode spacing to a suitable position using the regulator, turn on the vacuum pump, evacuate the vacuum chamber to below 7 kPa, and maintain a stable pressure value.

[0014] Step 2: Fill the vacuum chamber with inert gas until the pressure inside the vacuum chamber is between 9 and 20 kPa, and then turn on the high voltage to apply a 300-500V triangular voltage between the two electrodes.

[0015] Step 3: Adjust the electrode spacing by regulating the regulator, or control the gas pressure of the vacuum chamber after it is filled with inert gas, or inject diatomic gas into the vacuum chamber to control the discharge plasma between the electrodes, so as to generate a self-organized multilayer argon plasma with alternating light and dark phases.

[0016] The self-organized multilayer discharge plasma generation method further includes the following steps:

[0017] Step 4: Eliminate the layered discharge by continuing to fill with inert gas, adjusting the electrode spacing, or injecting diatomic gas.

[0018] In step two, the inert gas injected is argon.

[0019] In step four, the injected diatomic gas is oxygen or nitrogen with a molar fraction of 0.5% to 5%.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention provides a self-organized multilayer discharge plasma generation device and method. By optimizing the electrode structure and using gas discharge technology, inert gas discharge is used to form layered plasma. The basic principle behind the discharge layering phenomenon under these conditions is that the formation of layered plasma is related to the abundant metastable atoms generated during the discharge process. The stepwise ionization process caused by these metastable atoms leads to ionization instability. This instability propagates in the form of ionization waves, causing longitudinal amplitude modulation of plasma parameters, thus forming alternating bright and dark layered plasma. Adding a very small amount of diatomic molecular gas can effectively eliminate this layered discharge structure, making the plasma a continuous and stable discharge. The generated multilayered discharge plasma can be controllably eliminated.

[0022] 2. This invention can generate a self-organized multilayer discharge plasma that is clearly visible to the naked eye, distinct from the multilayer discharge plasma characteristics within a confined tube under low pressure (Pa level). Furthermore, this invention features a simple structure, a straightforward process, is environmentally friendly, and is continuously controllable. Generating and eliminating this multilayer discharge plasma is of guiding significance for exploring and studying the discharge process within gas lasers. This invention can be used to analyze multilayer discharge phenomena and plasma instabilities observed in some gas lasers and gas lamps, thereby improving the photoelectric performance of lasers and lamps. It has significant application value in laser fabrication, plasma control, and other fields.

[0023] 3. By adding diatomic molecular gas, this invention effectively quenches metastable argon atoms, reducing the source of step ionization; on the other hand, it changes the electron energy distribution function, making it tend towards the Maxwell distribution, thereby stabilizing the discharge. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a self-organized multilayer discharge plasma generation device provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a vertical cross-sectional schematic diagram of a self-organized multilayer discharge plasma generation device provided in Embodiment 1 of the present invention;

[0026] Figure 3 This is a top view of the upper flange in Embodiment 1 of the present invention;

[0027] Figure 4 This is a schematic diagram of observing self-organized multilayer discharge plasma through an observation window;

[0028] Figure 5 The images show the plasma discharge images obtained in Embodiment 2 of the present invention. In the image, (a) is an argon discharge image at a pressure of 20.17 kPa, and (b) is an argon discharge image at a pressure of 23.37 kPa.

[0029] In the diagram, 1 is the vacuum chamber, 2 is the upper flange, 3 is the handle, 4 is the observation window, 5 is the high-pressure flange, 6 is the electrode connector, 8 is the high-pressure power supply, 9 is the suction valve, 10 is the charging valve, 14 is the guide rail, 15 is the sliding support, 16 is the insulating rod, 17 is the hollow cylinder, 19 is the electrode transmission rod, 18 is the electrode, and 20 is the regulator. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figures 1-3 As shown, this embodiment of the invention provides a self-organized multilayer discharge plasma generation device, comprising: a vacuum chamber 1, on which two electrode connectors 6 are fixedly mounted via a high-voltage flange 5; a guide rail 14 is provided inside the vacuum chamber 1, on which two sliding supports 15 are mounted, each sliding support 15 having an insulating rod 16, and each insulating rod 16 having an electrode 18; the tips of the two electrodes 18 are arranged opposite each other to form a discharge body; and the electrode connectors 6 are connected to the electrodes 18 and the high-voltage flange 5 via wires. Source 8 is connected; one of the sliding supports 15 is fixedly connected to one end of the electrode transmission rod 19, and the other end of the electrode transmission rod 19 passes through the cavity wall of the vacuum chamber 1 and is connected to the regulator 20. The regulator 20 is fixedly installed on the cavity wall outside the vacuum chamber 1 and is used to push the electrode transmission rod 19, thereby driving one of the insulating rods 16 to slide along the guide rail 14 to adjust the distance between the two electrodes 18; the cavity wall of the vacuum chamber 1 is provided with a vacuum valve 9 and a gas filling valve 10. The vacuum valve 9 is connected to the vacuum pump, and the gas filling valve 10 is used to inject gas into the cavity.

[0033] Specifically, the self-organized multilayer discharge plasma generating device of this embodiment further includes a hollow cylinder 17, the bottom of which is fixedly connected to the insulating rod 16, and an electrode hole is provided in the center, with the electrode 18 horizontally disposed in the electrode hole. A connecting post is located at the bottom of the hollow cylinder 17, and the connecting post is sleeved on the top of the insulating rod 16 through the central connecting hole and fixed to the insulating rod 16 by bolts.

[0034] Specifically, in this embodiment, the adjuster 20 is a micrometer, and its frame is fixedly installed on the cavity wall of the vacuum cavity 1. The measuring rod passes through the cavity wall and is fixedly connected to the motor transmission rod 19. By rotating the measuring rod, the distance between the two electrodes can be adjusted. After calibration, the reading on the measuring rod can display the distance between the two electrodes.

[0035] Specifically, in this embodiment, the insulating rod 16 is made of polytetrafluoroethylene (PTFE), the sliding support 15 and guide rail 14 are made of stainless steel, the vacuum chamber 1 is made of stainless steel, and an upper flange 2 is provided on its top. The chamber can be opened through the upper flange 2 to adjust the electrode spacing inside the chamber. Handles 3 are respectively provided at the left and right ends of the upper flange 2, and an observation window 4 with an inner diameter of 35mm is provided in the center. The electrode 18 is a copper electrode. Furthermore, PTFE is used for insulation between the two electrode connectors 6 and the high-voltage flange 5.

[0036] Specifically, the high-voltage power supply 8 is used to generate a triangular wave voltage of 5–20 kHz. The volume (length × width × height) of the vacuum chamber 1 is 462 mm × 210 mm × 210 mm.

[0037] Furthermore, in this embodiment, a venting valve 11 and a vacuum measuring gauge 12 are also provided on the cavity wall of the vacuum chamber 1. The vacuum chamber 1 releases gas to the outside through the venting valve 11 to control the gas pressure of the vacuum chamber 1, and the vacuum measuring gauge 12 is used to measure the vacuum degree inside the vacuum chamber 1. In addition, the vacuum pump can be a rotary vane vacuum pump.

[0038] Example 2

[0039] Embodiment 2 of the present invention provides a method for generating self-organized multilayer discharge plasma, which is implemented using the self-organized multilayer discharge plasma generating device described in Embodiment 1, and includes the following steps:

[0040] Step 1: Adjust the electrode spacing to a suitable position using regulator 20, turn on the vacuum pump, evacuate the vacuum chamber 1 to below 7 kPa, and maintain a stable pressure value.

[0041] First, guide rails and electrodes need to be installed inside the vacuum chamber 1, and the distance between the electrodes needs to be set, for example, 1 to 2 mm. Then, the upper flange needs to be installed to ensure that the vacuum chamber is well sealed.

[0042] Step 2: Fill the vacuum chamber 1 with inert gas until the gas pressure inside the vacuum chamber 1 is between 9 and 20 kPa. Then, turn on the high voltage 8 to apply a 300-500V triangular voltage between the two electrodes, so as to generate discharge plasma between the electrodes. Specifically, the inert gas is argon.

[0043] Step 3: Adjust the electrode spacing by regulator 20 or control the vacuum chamber pressure after filling with inert gas to control the discharge plasma between electrodes, so as to generate a self-organized multilayer argon plasma with alternating light and dark phases.

[0044] In this embodiment, the preferred conditions for generating self-organized multilayer discharge plasma are: the voltage applied to the electrodes is 400V, the frequency of the triangular voltage is preferably 10kHz, the electrode spacing is 5mm, and after slowly filling with inert gas, the discharge plasma between the positive and negative electrodes will form a self-organized multilayer discharge plasma with alternating light and dark phases.

[0045] Step 4: Eliminate the layered discharge by continuing to fill with inert gas, adjusting the electrode spacing, or injecting diatomic gas.

[0046] In this embodiment, the number of discharge layers and the spacing between them can be adjusted by adjusting the electrode spacing and the vacuum chamber pressure.

[0047] Experiments have shown that increasing the electrode spacing to a suitable distance, such as 5-20 mm, can adjust the number of discharge layers. The multilayer discharge plasma morphology self-organizes, with one more discharge layer for every 2 mm increase in diameter, while the spacing between the discharge layers remains constant. Figure 4 As shown, the discharge plasma inside vacuum chamber 1 can be observed through the observation window at the top.

[0048] Experiments have shown that as inert gas is gradually introduced, and as the inert gas pressure in the chamber gradually increases to one standard atmosphere, the plasma morphology undergoes self-organization, forming a self-organized multilayered discharge plasma with alternating bright and dark phases. The number of discharge layers then increases and becomes denser. Figure 5 As shown in a and b.

[0049] The experiment also found that after argon discharge stratification (9-20 kPa) is generated, if nitrogen is slowly introduced to increase the chamber pressure to 24 kPa, the multilayer plasma morphology will spontaneously organize into a continuous columnar plasma, and the stratified discharge will disappear.

[0050] Therefore, in this invention, the layered discharge can be eliminated by injecting diatomic gas. The diatomic molecular gas introduced has a molar fraction of 0.5% to 5%, and nitrogen gas with a molar fraction of 2% is gradually introduced. The layered structure of the argon multilayer discharge plasma gradually becomes a continuous structure, and the multilayer discharge is effectively eliminated. When nitrogen gas with a molar fraction of 5% is introduced, the plasma is extinguished.

[0051] Therefore, in this embodiment, diatomic molecules can also be injected to control the number of discharge layers and the spacing between each discharge layer. Furthermore, the elimination of layered discharge can be achieved by adjusting the gas pressure, regulating the electrode spacing, or injecting diatomic gas.

[0052] In this embodiment, after generating multilayer discharge plasma, the guide rail mechanism is slowly controlled to increase the electrode spacing from 5mm to 20mm. The multilayer discharge plasma morphology self-organizes, with one more discharge layer for every 2mm increase in diameter, while the spacing between the discharge layers remains unchanged. Besides adjusting the gas pressure and electrode spacing, the morphology of the self-organized multilayer discharge plasma can be controlled by injecting a diatomic gas that can effectively quench metastable argon atoms.

[0053] This invention discovers a self-organized argon multilayer discharge plasma within an unconstrained tube (free space) chamber at relatively high pressures (kPa level). Furthermore, it reveals the manifestation of discharge instability in this multilayer discharge plasma, which is related to the volume loss rate of charged particles, with dissociation and recombination being the primary pathway for charged particle loss. This instability is associated with inert gases, such as He2 (helium). + The vibrational-rotational population is relevant because the potential energy curves of the molecular and antibonded states intersect in the third vibrational energy level region. This leads to a strong nonlinear relationship between the recombination rate and electron and gas temperatures (from the Boltzmann distribution at gas temperature to the Boltzmann distribution at electron temperature, depending on the discharge conditions). This invention contributes to understanding the stratification and contraction properties of helium discharge under various conditions, revealing the main physical mechanisms of helium discharge instability and filling some gaps in our understanding of such instability. Furthermore, this invention has significant applications in laser fabrication, plasma control, and other fields.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-organizing multilayer discharge plasma generation device, characterized in that, include: A vacuum chamber (1) has two electrode connectors (6) fixedly mounted on its wall via a high-pressure flange (5). A guide rail (14) is installed inside the vacuum chamber (1), and two sliding supports (15) are mounted on the guide rail (14). Each sliding support (15) has an insulating rod (16), and each insulating rod (16) has an electrode (18). The tips of the two electrodes (18) are positioned opposite each other to form a discharge body. The electrode connectors (6) are connected by wires. It is connected to the electrode (18) and the high voltage power supply (8); one of the sliding supports (15) is fixedly connected to one end of the electrode transmission rod (19), and the other end of the electrode transmission rod (19) passes through the cavity wall of the vacuum cavity (1) and is connected to the regulator (20). The regulator (20) is fixedly set on the cavity wall outside the vacuum cavity (1) and is used to push the electrode transmission rod (19), thereby driving one of the insulating rods (16) to slide along the guide rail (14) to adjust the distance between the two electrodes (18); The vacuum chamber (1) is provided with a vacuum valve (9) and a gas filling valve (10) on its wall. The vacuum valve (9) is connected to a vacuum pump, and the gas filling valve (10) is used to inject gas into the chamber.

2. The self-organized multilayer discharge plasma generation device according to claim 1, characterized in that, It also includes a hollow cylinder (17), the bottom of which is fixedly connected to the insulating rod (16), and an electrode hole is provided in the center, and the electrode (18) is horizontally arranged in the electrode hole.

3. The self-organized multilayer discharge plasma generation device according to claim 1, characterized in that, The regulator is a micrometer (20).

4. The self-organized multilayer discharge plasma generation device according to claim 1, characterized in that, The insulating rod (16) is made of polytetrafluoroethylene, the sliding support (15) and the guide rail (14) are made of stainless steel, the vacuum cavity (1) is made of stainless steel, and an upper flange (2) is provided on its top. The upper flange (2) has handles (3) on its left and right ends respectively, and an observation window (4) is provided in the center. The electrode (18) is a copper electrode.

5. The self-organized multilayer discharge plasma generation device according to claim 1, characterized in that, The high-voltage power supply (8) is used to generate a voltage with a frequency of 5 to 20 kHz.

6. The self-organized multilayer discharge plasma generation device according to claim 1, characterized in that, The vacuum chamber (1) is also provided with a vent valve (11) and a vacuum measuring gauge (12) on its cavity wall. The vent valve (11) is used to release gas to control the gas pressure in the vacuum chamber (1), and the vacuum measuring gauge (12) is used to measure the vacuum degree in the vacuum chamber (1).

7. A method for generating self-organized multilayer discharge plasma, characterized in that, The self-organized multilayer discharge plasma generation device according to claim 1 is implemented by comprising the following steps: Step 1: Adjust the electrode spacing to a suitable position using the regulator (20), turn on the vacuum pump, evacuate the vacuum chamber (1) to below 7 kPa, and keep the pressure value stable. Step 2: Fill the vacuum chamber (1) with inert gas until the gas pressure inside the vacuum chamber (1) is between 9 and 20 kPa, and then turn on the high voltage (8) to apply a 300-500V triangular voltage between the two electrodes; Step 3: Adjust the electrode spacing by adjusting the regulator (20), or control the gas pressure of the vacuum chamber (1) after it is filled with inert gas, or inject diatomic gas into the vacuum chamber (1) to control the discharge plasma between the electrodes, so as to generate a self-organized multilayer argon plasma with alternating light and dark phases.

8. The method for generating self-organized multilayer discharge plasma according to claim 7, characterized in that, It also includes the following steps: Step 4: Eliminate the layered discharge by continuing to fill with inert gas, adjusting the electrode spacing, or injecting diatomic gas.

9. The method for generating self-organized multilayer discharge plasma according to claim 8, characterized in that, In step two, the inert gas injected is argon. In step four, the injected diatomic gas is oxygen or nitrogen with a molar fraction of 0.5% to 5%.

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