A cascade arc plasma generator

Abstract

The invention relates to the field of plasma technology, and discloses a cascade arc plasma generator, which comprises a cathode structure, a cascade structure and an anode structure connected in sequence. When the cascade arc plasma generator is working, a working gas to be ionized enters an ionization chamber through an air inlet channel, a potential difference exists between a plurality of arc starting needles and an anode body, the plurality of arc starting needles all break down the working gas, the working gas is ionized, and plasma is formed, and is ejected to the outside of the cascade arc plasma generator through the ionization chamber, the plasma channel and the anode channel connected in sequence, enters an external device, and interacts with a material sample. The plurality of arc starting needles are parallel to each other and arranged at intervals, and the needle tips are all located in the same plane to form a planar plasma source, which can irradiate a large area of ​​material samples or irradiate a plurality of material samples at one time, and the arrangement of the plurality of arc starting needles can also be changed to be suitable for material samples of different shapes, so as to improve the irradiation efficiency.

Description

Technical Field

[0001] The invention relates to the field of plasma technology, in particular to a cascade arc plasma generator. Background Art

[0002] Controlled nuclear fusion has the advantages of being safe, clean, and fuel-rich, and is one of the main options for solving future energy problems. Currently, there are two common methods for achieving controlled nuclear fusion: magnetic confinement fusion and inertial confinement fusion. The principle of inertial confinement fusion is relatively simple, which is to use the huge pressure generated by lasers to reduce the volume of nuclear fuel in a very short time and increase its density, so that the atomic nuclei undergo fusion reactions and release energy. Magnetic confinement fusion, on the other hand, uses magnetic fields to confine nuclear fuel in extremely high-temperature plasma to make it react.

[0003] However, in a magnetic confinement nuclear fusion device, there will be a strong interaction between the strong heat flux and strong particle flow from the high-temperature plasma and the wall directly facing the plasma, which will not only cause damage to the first wall, cause plasma energy radiation loss and reduce plasma confinement performance, but also directly affect the plasma density control. Therefore, it is necessary to study the mechanism of interaction between plasma and wall materials in order to develop materials that can withstand the plasma environment. These materials usually need to have high heat resistance, radiation stability, chemical inertness and other characteristics to ensure the safe and stable operation of fusion reactors.

[0004] In the study of the interaction mechanism between fusion reactor plasma and materials, it is necessary to provide a plasma environment. Currently, related experiments usually use a plasma generator to provide the plasma environment. Among various plasma generators, the plasma generated by the cascade arc plasma generator has a high energy density and is more suitable for the study of the interaction mechanism between fusion reactor plasma and materials.

[0005] The cascade arc plasma generator in the prior art is usually a single cathode or a triple cathode cascade arc plasma generator. The single cathode cascade arc plasma generator has one cathode with an arc starting needle, and the triple cathode cascade arc plasma generator has three cathodes each with an arc starting needle, and the three arc starting needle tips meet at one point. Regardless of whether it is a single cathode or a triple cathode, affected by the arc starting principle and structure, the generated plasma is a point source. In the study of the interaction between fusion reactor plasma and materials, it is impossible to irradiate multiple material samples or irradiate large-area material samples at one time, which greatly affects the efficiency of irradiation and increases the cost of a single test study. Summary of the invention

[0006] The purpose of the present invention is to provide a cascade arc plasma generator to solve the problem that the existing cascade arc plasma generator cannot irradiate multiple material samples or irradiate large-area material samples at one time.

[0007] In order to achieve the above object, the present invention provides a cascade arc plasma generator, which comprises a cathode structure, a cascade structure and an anode structure connected in sequence according to a plasma ejection direction;

[0008] The cathode structure comprises a cathode assembly and a cathode seat, wherein the cathode assembly comprises an arc-starting needle seat and a plurality of arc-starting needles, wherein the plurality of arc-starting needles are parallel to each other and are connected to one end of the arc-starting needle seat at intervals; an ionization chamber is provided on the cathode seat, wherein the ionization chamber penetrates the cathode seat along a plasma ejection direction, wherein the arc-starting needle seat is partially arranged in the ionization chamber, so that the plurality of arc-starting needles are all located in the ionization chamber, and the needle tips of the plurality of arc-starting needles are arranged toward the cascade structure, and the needle tips of the plurality of arc-starting needles are all located in the same plane, and the plane is perpendicular to the plasma ejection direction; a plurality of air inlet channels are also provided on the cathode seat, and the air inlet channels are used to transport gas into the ionization chamber;

[0009] The anode structure comprises an anode body, wherein the anode body is provided with an anode channel penetrating the upper and lower surfaces thereof;

[0010] The cascade structure includes a plurality of cascade sheets, which are stacked in sequence along the plasma jetting direction and arranged between the cathode seat and the anode body; each cascade sheet is provided with a cascade channel, which runs through the cascade sheet along the plasma jetting direction, so that when the plurality of cascade sheets are stacked, the plurality of cascade channels are connected in sequence to form a plasma channel; the ionization chamber, the plasma channel and the anode channel are arranged relatively to each other and connected in sequence.

[0011] Furthermore, a first protrusion is provided at the end of the arc-starting needle seat facing the cascade structure, the first protrusion is embedded in the ionization chamber, and the arc-starting needle is provided on the end surface of the first protrusion.

[0012] Furthermore, the cathode structure also includes a water cooling component;

[0013] A first installation cavity is formed at one end of the arc-starting needle seat away from the arc-starting needle, and the water-cooling component is sealed and connected to the first installation cavity.

[0014] Furthermore, the water cooling assembly includes a water cooling box, a water inlet pipe and a water outlet pipe;

[0015] The water cooling box is sealed and connected to the first installation cavity, a gap is provided between the bottom surface of the water cooling box and the bottom surface of the first installation cavity, and a cooling channel is formed by enclosing the outer wall of the water cooling box and the cavity wall of the first installation cavity, a water inlet channel and a water outlet channel are provided in the water cooling box, the water inlet channel and the water outlet channel both penetrate the two side surfaces of the water cooling box in the plasma spraying direction, and the water inlet channel and the water outlet channel are respectively communicated with the cooling channel;

[0016] The water inlet pipe is connected to the water inlet channel, and the water outlet pipe is communicated with the water outlet channel.

[0017] Furthermore, the cathode structure further comprises a protection ring, which is arranged in the ionization chamber and is sealed and connected to the inner wall of the ionization chamber; the protection ring comprises a sleeve connection portion and an injection portion which are sequentially arranged along the plasma injection direction, the sleeve connection portion is provided with a sleeve connection channel, the injection portion is provided with an injection channel, and the sleeve connection channel is connected to the injection channel;

[0018] The sleeve portion is sleeved on the outside of the first protrusion, and the inner surface of the sleeve portion is in close contact with the outer surface of the first protrusion, and the outer surface of the sleeve portion is in close contact with the cavity wall of the ionization chamber;

[0019] The injection part is arranged outside the needle tip of the plurality of arc-starting needles, and there is a gap between its inner surface and each of the arc-starting needles. The outer surface of the injection part is in close contact with the cavity wall of the ionization chamber, and the diameter of the injection channel gradually decreases from top to bottom.

[0020] Furthermore, it also includes a connection structure, which includes a flange, a plurality of connection rods and a plurality of sets of locking nuts, the number of which is the same as that of the connection rods;

[0021] The flange cover is arranged above the end of the arc-starting needle seat away from the arc-starting needle, and the flange is also provided with first connecting holes with the same number as the connecting rods. Each of the connecting rods is arranged along the plasma injection direction, one end of which is fixed on the anode body, and the other end passes through the first connecting hole and is fastened to a group of the locking nuts, and the connecting rods are made of insulating material.

[0022] Furthermore, the cascade structure further comprises a plurality of first gaskets and second gaskets, and a first gasket is arranged between two adjacent cascade gaskets;

[0023] The second gasket is arranged between the cathode seat and the uppermost cascade sheet in the cascade structure;

[0024] The first gasket and the second gasket are both annular structures, so that adjacent cascade channels are connected.

[0025] Furthermore, the angle of the needle tip of the arc-starting needle is 30°~45°.

[0026] Furthermore, the cascade structure includes 5 to 11 cascade pieces.

[0027] Compared with the prior art, the cascade arc plasma generator provided by the present invention has the following beneficial effects:

[0028] The present invention provides a cascade arc plasma generator, which comprises a cathode structure, a cascade structure and an anode structure connected in sequence according to a plasma ejection direction. When the cascade arc plasma generator is working, a working gas to be ionized enters the ionization chamber through the air inlet channel, and there is a potential difference between a plurality of arc starting needles and an anode body. The plurality of arc starting needles all break down the working gas, and the working gas is ionized to form plasma, and is ejected to the outside of the cascade arc plasma generator through the ionization chamber, the plasma channel and the anode channel connected in sequence, and enters an external device to interact with a material sample to be studied. The plurality of arc starting needles are parallel to each other and arranged at intervals, and the needle tips thereof are all located in the same plane, and the plane is perpendicular to the plasma ejection direction to form a planar plasma source, which can irradiate a large area of ​​material samples or irradiate a plurality of material samples at a time, and can also be suitable for material samples of different shapes by changing the arrangement of the plurality of arc starting needles, so as to improve the irradiation efficiency and accelerate the experimental research process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional schematic diagram of a cascade arc plasma generator according to an embodiment of the present invention;

[0030] Figure 2 is a partial cross-sectional schematic diagram of a three-dimensional structure of a cascade arc plasma generator according to an embodiment of the present invention;

[0031] Figure 3 yes Figure 1 A magnified schematic diagram of the middle A area;

[0032] Figure 4 yes Figure 3 A magnified schematic diagram of area B.

[0033] In the figure, 100, cascade arc plasma generator; 1, cathode structure; 11, cathode assembly; 111, arc-starting needle seat; 1111, first protrusion; 11111, first mounting groove; 1112, first mounting cavity; 112, arc-starting needle; 12, cathode seat; 121, ionization cavity; 122, air inlet channel; 123, second mounting groove; 1231, second mounting surface; 13, water cooling assembly; 131, water cooling box; 1311, cooling channel; 1312, water inlet channel; 1313, water outlet channel; 132, water inlet pipe; 133, water outlet pipe; 14. Protective ring; 141. Socket part; 1411. Socket channel; 1412. First convex ring; 14121. First mounting surface; 142. Injection part; 1421. Injection channel; 15. Inlet pipe; 2. Cascade structure; 21. Cascade sheet; 211. Cascade channel; 22. Plasma channel; 23. First gasket; 24. Second gasket; 3. Anode structure; 31. Anode body; 311. Anode channel; 312. Second connecting hole; 32. Cooling pipe; 4. Connecting structure; 41. Flange; 42. Connecting rod; 43. Locking nut. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0035] like Figure 1~Figure 4 As shown, a cascade arc plasma generator 100 according to an embodiment of the present invention comprises a cathode structure 1, a cascade structure 2 and an anode structure 3 connected in sequence along a plasma ejection direction X; the cathode structure 1 comprises a cathode assembly 11 and a cathode seat 12, the cathode assembly 11 comprises an arc-starting needle seat 111 and a plurality of arc-starting needles 112, the plurality of arc-starting needles 112 are parallel to each other and are connected to one end of the arc-starting needle seat 111 at intervals; an ionization chamber 121 is provided on the cathode seat 12, and the ionization chamber 121 is connected along the plasma ejection direction X passes through the cathode seat 12, and the arc-starting needle seat 111 is partially arranged in the ionization chamber 121, so that the plurality of arc-starting needles 112 are all located in the ionization chamber 121, and the needle tips of the plurality of arc-starting needles 112 are arranged toward the cascade structure 2, and the needle tips of the plurality of arc-starting needles 112 are all located in the same plane, and the plane is perpendicular to the plasma injection direction X; a plurality of air inlet channels 122 are also opened on the cathode seat 12, and the air inlet channels 122 are used to transport gas to the ionization chamber 121.

[0036] The anode structure 3 includes an anode body 31, in which an anode channel 311 is provided that runs through the upper and lower surfaces thereof; the cascade structure 2 includes a plurality of cascade sheets 21, which are stacked along the plasma injection direction X and arranged between the cathode seat 12 and the anode body 31; each cascade sheet 21 is provided with a cascade channel 211, which runs through the cascade sheet 21 along the plasma injection direction X, so that when the plurality of cascade sheets 21 are stacked, the plurality of cascade channels 211 are connected in sequence to form a plasma channel 22; the ionization chamber 121, the plasma channel 22 and the anode channel 311 are arranged relatively to each other and are connected in sequence.

[0037] Based on the above technical solution, when the cascade arc plasma generator 100 is working, the working gas to be ionized enters the ionization chamber 121 through the air inlet channel 122, and there is a potential difference between the cathode assembly 11 and the anode body 31. Under the action of the arc starting needle 112, the working gas is electrically broken down to be ionized, thereby forming plasma. Since the plurality of arc starting needles are parallel to each other and arranged at intervals, the needle tips of the plurality of arc starting needles 112 are also located in the same plane. Therefore, when the plurality of arc starting needles 112 electrically break down the working gas, a planar plasma source will be formed, thereby irradiating a large area of ​​material samples or irradiating a plurality of material samples at a time. The arrangement of the plurality of arc starting needles can also be changed to be suitable for material samples of different shapes. The plasma passes through the ionization chamber 121, the plasma channel 22 and the anode channel 311 in sequence and is ejected to the cascade arc plasma generator 100 to interact with the material samples in the external device.

[0038] Preferably, if Figure 1 and Figure 4 As shown, the maximum distance between two adjacent arc-starting needles 112 is defined as D1, and the diameter of each arc-starting needle 112 is defined as D2. In this embodiment, 0.1*D2≤D1≤0.2*D2, and D1 should not be too large or too small. If D1 is too small, the two adjacent arc-starting needles 112 are relatively close and may contact each other, resulting in only one point-like plasma source. If D1 is too large, the two adjacent arc-starting needles 112 are far apart, which will cause multiple arc-starting needles to eventually form multiple point-like plasma sources, and none of them can smoothly form a surface-like plasma source.

[0039] Preferably, if Figure 1 As shown, in order to ensure the irradiation effect of the cascade arc plasma generator 100 and reduce the interaction between plasma and cascade sheet materials, the ionization chamber 121 , the plasma channel 22 and the anode channel 311 are all coaxially arranged, and the diameter of the plasma channel 22 matches the diameter of the ionization chamber 121 .

[0040] Preferably, the cathode structure 1 further comprises an air inlet pipe 15 , which is connected to the air inlet channel 122 , so as to facilitate the communication between the air inlet channel 122 and an external gas source, thereby facilitating the working gas to enter the ionization chamber 121 via the air inlet channel 122 .

[0041] Furthermore, if Figure 1 and Figure 2 As shown, in order to facilitate the installation of the arc-starting needle seat 111 into the ionization chamber 121 , the arc-starting needle seat 111 is provided with a first protrusion 1111 at the end facing the cascade structure 2 , the first protrusion 1111 is embedded in the ionization chamber 121 , and the arc-starting needle 112 is arranged on the end face of the first protrusion 1111 .

[0042] Preferably, if Figure 1 and Figure 3 As shown, to facilitate the installation and positioning of the arc-starting needle 112, a plurality of first installation grooves 11111 for installing the arc-starting needle 112 are opened at the end of the first protrusion 1111. The number of the first installation grooves 11111 in this embodiment is the same as the arc-starting needle 112, so that the arc-starting needle 112 is installed in each of the first installation grooves 11111; but in some other embodiments, the number and arrangement of the first installation grooves 11111 can be set in combination with a variety of commonly used arrangement methods, so that a planar plasma source suitable for the material sample can be formed by installing the arc-starting needle 112 in some of the first installation grooves 11111, so as to improve the applicability of the arc-starting needle holder 111.

[0043] Furthermore, if Figure 1 and Figure 2 As shown, since the cathode assembly 11 will heat up during the operation of the cascade arc plasma generator 100, it needs to be cooled to ensure its normal operation; therefore, the cathode structure 1 also includes a water cooling assembly 13; a first installation cavity 1112 is provided at one end of the arc starting needle seat 111 away from the arc starting needle 112, and the water cooling assembly 13 is sealed and connected to the first installation cavity 1112.

[0044] Furthermore, if Figure 1 and Figure 2As shown, in order to realize cooling of the cathode assembly 11 by the water cooling assembly 13, the water cooling group 13 includes a water cooling box 131, a water inlet pipe 132 and a water outlet pipe 133; the water cooling box 131 is sealed and connected to the first installation cavity 1112, and there is a gap between the bottom surface of the water cooling box 131 and the bottom surface of the first installation cavity 1112, and a cooling channel 1311 is formed by the outer wall of the water cooling box 131 and the cavity wall of the first installation cavity 1112; in this embodiment, the water cooling box 131 is sealed and welded to the first installation cavity 1112, so that the water cooling box 131 and the arc starting needle seat 111 are fixedly connected to form a whole, and while realizing the connection, it is possible to realize sealing or further improve the sealing effect by welding, thereby preventing coolant leakage. A water inlet channel 1312 and a water outlet channel 1313 are provided in the water cooling box 131, and the water inlet channel 1312 and the water outlet channel 1313 both penetrate the two side surfaces of the water cooling box 131 in the plasma jet direction X, and the water inlet channel 1312 and the water outlet channel 1313 are respectively connected to the cooling channel 1311; the water inlet pipe 132 is connected to the water inlet channel 1312, and the water outlet pipe 133 is connected to the water outlet channel 1313, and an external coolant is connected through the water inlet pipe 132, so that the coolant enters the cooling channel 1311 through the water inlet channel 1312 to cool the cathode assembly 11, and then is discharged to an external device through the water outlet channel 1313 and the water outlet pipe 133.

[0045] Furthermore, if Figure 1~Figure 4As shown, in order to protect the cathode seat 12 and reduce the interaction between the plasma and the cathode seat 12, the cathode structure 1 also includes a protection ring 14, the protection ring 14 is arranged in the ionization chamber 121, and the protection ring 14 is sealed and connected to the inner wall of the ionization chamber 121; in this embodiment, the protection ring 14 is sealed and welded to the cavity wall of the ionization chamber 121 to prevent the protection ring 14 from moving, thereby ensuring the protection effect of the protection ring 14 on the cathode seat 12; the protection ring 14 includes a sleeve portion 141 and an injection portion 142 which are sequentially arranged along the plasma injection direction X, the sleeve portion 141 is provided with a sleeve channel 1411, the injection portion 142 is provided with an injection channel 1421, the sleeve The channel 1411 is connected with the injection channel 1421; the sleeve portion 141 is sleeved on the outside of the first protrusion 1111, and its inner surface is in close contact with the outer surface of the first protrusion 1111, and the outer surface of the sleeve portion 141 is in close contact with the cavity wall of the ionization chamber 121 to protect the cathode seat 12; the injection portion 142 is arranged on the outside of the needle tip of the plurality of arc-starting needles 112, and there is a gap between its inner surface and each of the arc-starting needles 112, and the outer surface of the injection portion 142 is in close contact with the cavity wall of the ionization chamber 121, and along the moving direction of the plasma, the diameter of the injection channel 1421 gradually decreases to form a nozzle-like shape to facilitate the injection of plasma.

[0046] Preferably, if Figure 1~Figure 4 As shown, to facilitate the installation and positioning of the protective ring 14, a first convex ring 1412 is provided on the outer periphery of one end of the sleeve portion 141 away from the arc-starting needle 112, and the first convex ring 1412 includes a first mounting surface 14121 facing the cascade structure 2, and a second mounting groove 123 is correspondingly provided on the end of the cathode seat 12 away from the cascade structure 2; the first convex ring 1412 is snapped into the second mounting groove 123, and the second mounting groove 123 includes a second mounting surface 1231 opposite to the first mounting surface 14121, and when the protective ring 14 is installed to the ionization chamber 121, the second mounting surface 1231 is in close contact with the first mounting surface 14121 to ensure that the protective ring 14 is welded to the set position to protect the ionization chamber 121.

[0047] Furthermore, if Figure 1 and Figure 2As shown, it also includes a connecting structure 4, which includes a flange 41, a plurality of connecting rods 42 and a plurality of groups of locking nuts 43 with the same number as the connecting rods 42; the flange 41 is covered above the end of the arc-starting needle seat 111 away from the arc-starting needle 112, and the flange 41 is also provided with a number of first connecting holes with the same number as the connecting rods 42, each of the connecting rods 42 is arranged along the moving direction of the plasma, one end of which is fixed on the anode body 31, and the other end passes through the first connecting hole and is fastened to a group of locking nuts 43, so that the cathode structure 1, the cascade structure 2 and the anode structure 3 are connected and combined into a whole, which is beneficial to ensure the airtightness of the plasma channel; the connecting rod 42 is made of insulating material to insulate the cathode structure 1 and the anode structure 3.

[0048] Preferably, if Figure 2 As shown, in order to avoid the flange 41 from interfering with the water cooling box 131 and being unable to cover the end of the arc starting needle seat 111 away from the arc starting needle 112, the flange 41 is provided with a connecting channel, and the connecting channel passes through the flange 41 along the plasma moving direction X, so that the flange 41 is sleeved on the outer periphery of the water cooling box 131 and covers the end of the arc starting needle seat 111 away from the arc starting needle 112.

[0049] Furthermore, if Figure 1 and Figure 2 As shown, in order to make the plasma channel 22 form an airtight channel, the cascade structure 2 also includes a plurality of first gaskets 23 and second gaskets 24, and the first gasket 23 is arranged between two adjacent cascade plates 21; the second gasket 24 is arranged between the cathode seat 12 and the topmost cascade plate 21 in the cascade structure 2; the first gasket 23 and the second gasket 24 are both annular structures, so that the adjacent cascade channels 211 are connected.

[0050] Furthermore, if Figure 1 As shown, the tip angle of the arc starting needle 112 is 30°~45°. If the tip angle of the arc starting needle 112 is too large, it is difficult to achieve arc discharge at the tip to form plasma. If the tip angle of the arc starting needle 112 is too small, the tip will be easily ablated in a short time and arc discharge cannot be initiated, increasing the use and maintenance costs. The arc starting needle 112 in this embodiment is made of pure tungsten.

[0051] Preferably, if Figure 1 and Figure 3As shown, in the radial orthographic projection along the arc-starting needle 112, the inner wall of the injection channel 1421 and the needle tip bevel of the arc-starting needle 112 are parallel, so that the injection channel 1421 and the needle tip of the arc-starting needle 112 are arranged correspondingly, which is beneficial to improving the injection efficiency of the plasma.

[0052] Furthermore, if Figure 1 As shown, the cascade structure includes 5 to 11 cascade plates, which can control the production cost of the cascade arc plasma generator 100 while ensuring sufficient plasma concentration.

[0053] Preferably, if Figure 1 As shown, in order to facilitate the connection between the cascade arc plasma generator 100 and external equipment, a plurality of second connection holes 312 are opened at the bottom end of the anode body 31 .

[0054] Preferably, if Figure 1 and Figure 2 As shown, in addition to the cathode assembly 11 needing to be cooled, the anode body 31 also needs to be cooled. The anode structure 3 includes a cooling tube 32. A cooling channel is provided in the anode body 31. The cooling tube 32 is connected to the cooling channel.

[0055] Preferably, if Figure 1 As shown, since plasma tends to diffuse after being formed and ejected, in order to reduce the impact of plasma on the anode body 31 and to increase the service life of the anode body 31, the diameter of the anode channel 311 gradually expands from top to bottom to form a trumpet shape, thereby reducing the interaction between plasma and the inner wall material of the anode channel 311 and sputtering the material into the plasma.

[0056] The working process of the present invention is as follows: the working gas to be ionized enters the ionization chamber 121 from the air inlet channel 122, there is a potential difference between the cathode assembly 11 and the anode body 31, under the action of the plurality of arc starting needles 112 arranged in parallel and at intervals, the working gas is electrically broken down, the working gas is ionized to generate plasma, the plurality of arc starting needles 112 work together to form a planar plasma source of a certain area, thereby distinguishing it from a single-point or multi-point plasma source; under the action of the potential difference, the plasma starts from the ionization chamber 121, passes through the plasma channel 22 and the anode channel 311 in sequence, is ejected from the cascade arc plasma generator 100, reaches the vacuum chamber in the external equipment, and interacts with the material sample in the vacuum chamber.

[0057] In summary, the embodiment of the present invention provides a cascade arc plasma generator, which, under the action of the arc starting needle 112, electrically breaks down the working gas to ionize it, thereby forming plasma. The multiple arc starting needles 112 arranged in parallel and at intervals act simultaneously to break down the working gas, and since the needle tips of the multiple arc starting needles 112 are all located in the same plane, a planar plasma source is formed. The plasma is formed in the ionization chamber 121, and sequentially passes through the plasma channel 22 and the anode channel 311, and is ejected from the cascade arc plasma generator 100, enters the external device, and then interacts with the material sample; the planar plasma source formed by the multiple arc starting needles 112 arranged in parallel and at intervals breaks through the limitation of the small irradiation area of ​​the current cascade arc plasma generator, and can irradiate a large area of ​​material samples or irradiate multiple material samples at a time, thereby improving efficiency and accelerating the experimental research process.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A cascade arc plasma generator, characterized in that: It includes a cathode structure, a cascade structure and an anode structure connected in sequence according to the plasma injection direction; The cathode structure comprises a cathode assembly and a cathode seat, wherein the cathode assembly comprises an arc-starting needle seat and a plurality of arc-starting needles, wherein the plurality of arc-starting needles are parallel to each other and are connected to one end of the arc-starting needle seat at intervals; an ionization chamber is provided on the cathode seat, wherein the ionization chamber penetrates the cathode seat along a plasma ejection direction, wherein the arc-starting needle seat is partially arranged in the ionization chamber, so that the plurality of arc-starting needles are all located in the ionization chamber, and the needle tips of the plurality of arc-starting needles are arranged toward the cascade structure, and the needle tips of the plurality of arc-starting needles are all located in the same plane, and the plane is perpendicular to the plasma ejection direction; a plurality of air inlet channels are also provided on the cathode seat, and the air inlet channels are used to transport gas into the ionization chamber; The arc-starting needle seat is provided with a first protrusion at the end facing the cascade structure, the first protrusion is embedded in the ionization chamber, and the arc-starting needle is provided on the end surface of the first protrusion; The cathode structure further comprises a protection ring, which is arranged in the ionization chamber and is sealed and connected to the inner wall of the ionization chamber; the protection ring comprises a sleeve connection portion and an injection portion which are sequentially arranged along the plasma injection direction, the sleeve connection portion is provided with a sleeve connection channel, the injection portion is provided with an injection channel, and the sleeve connection channel is communicated with the injection channel; The sleeve portion is sleeved on the outside of the first protrusion, and the inner surface of the sleeve portion is in close contact with the outer surface of the first protrusion, and the outer surface of the sleeve portion is in close contact with the cavity wall of the ionization chamber; The injection part is arranged outside the needle tip of the plurality of arc-starting needles, and there is a gap between the inner surface of the injection part and each of the arc-starting needles, the outer surface of the injection part is in close contact with the cavity wall of the ionization chamber, and the diameter of the injection channel gradually decreases from top to bottom; The anode structure comprises an anode body, wherein the anode body is provided with an anode channel penetrating the upper and lower surfaces thereof; The cascade structure comprises a plurality of cascade sheets, which are stacked in sequence along the plasma ejection direction and arranged between the cathode seat and the anode body; each cascade sheet is provided with a cascade channel, which penetrates the cascade sheet along the plasma ejection direction, so that when the plurality of cascade sheets are stacked, the plurality of cascade channels are connected in sequence to form a plasma channel; The ionization chamber, plasma channel and anode channel are arranged opposite to each other and are connected in sequence.

2. The cascade arc plasma generator according to claim 1, characterized in that The cathode structure also includes a water cooling assembly; A first installation cavity is formed at one end of the arc-starting needle seat away from the arc-starting needle, and the water-cooling component is sealed and connected to the first installation cavity.

3. The cascade arc plasma generator according to claim 2, characterized in that: The water cooling assembly comprises a water cooling box, a water inlet pipe and a water outlet pipe; The water cooling box is sealed and connected to the first installation cavity, a gap is provided between the bottom surface of the water cooling box and the bottom surface of the first installation cavity, and a cooling channel is formed by enclosing the outer wall of the water cooling box and the cavity wall of the first installation cavity, a water inlet channel and a water outlet channel are provided in the water cooling box, the water inlet channel and the water outlet channel both penetrate the two side surfaces of the water cooling box in the plasma spraying direction, and the water inlet channel and the water outlet channel are respectively communicated with the cooling channel; The water inlet pipe is connected to the water inlet channel, and the water outlet pipe is communicated with the water outlet channel.

4. The cascade arc plasma generator according to claim 1, characterized in that Also included is a connection structure, the connection structure comprising a flange, a plurality of connection rods and a plurality of sets of locking nuts having the same number as the connection rods; The flange cover is arranged above the end of the arc-starting needle seat away from the arc-starting needle, and the flange is also provided with first connecting holes with the same number as the connecting rods. Each of the connecting rods is arranged along the plasma injection direction, one end of which is fixed on the anode body, and the other end passes through the first connecting hole and is fastened to a group of the locking nuts, and the connecting rods are made of insulating material.

5. The cascade arc plasma generator according to claim 1, characterized in that: The cascade structure further includes a plurality of first gaskets and second gaskets, wherein the first gasket is arranged between two adjacent cascade gaskets; The second gasket is arranged between the cathode seat and the uppermost cascade sheet in the cascade structure; The first gasket and the second gasket are both annular structures, so that adjacent cascade channels are connected.

6. The cascade arc plasma generator according to claim 1, characterized in that The angle of the needle tip of the arc starting needle is 30° to 45°.

7. The cascade arc plasma generator according to claim 1, characterized in that: The cascade structure includes 5 to 11 cascade sheets.

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