Plasma generating device

Abstract

The invention relates to the technical field of plasma sources, and discloses a plasma generating device, which comprises an anode part, a cathode part and a power supply part, and is characterized in that the anode part comprises a shell and an anode flange which are connected with each other, and an ionization cavity and a plasma channel which are communicated with each other are formed in the shell; the cathode part comprises a cathode flange and two heating electrodes, the two heating electrodes are respectively connected with a first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet which are arranged at an interval, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are connected through a graphite connecting block, the cathode part further comprises a gas inlet part, and the gas inlet part is used for filling ionization gas into the ionization cavity. According to the cathode, the heating electrodes are directly connected with the two ends of the lanthanum hexaboride part, the temperature of the whole lanthanum hexaboride part is uniformly increased, the problem of thermal stress concentration of a traditional bent structure is avoided, the risk of material fragmentation is reduced, the reliability of the lanthanum hexaboride part is ensured, and the service life of the whole plasma generation device is further prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma sources, and particularly to a plasma generating device. Background Art

[0002] Thermionic cathode plasma sources are widely used in the industrial field due to their stable electron emission and excellent plasma uniformity. Compared with arc plasma sources (high density but poor stability) and ECR plasma sources (insufficient density), thermionic cathode types exhibit balanced density and stability advantages when simulating the divertor environment of nuclear fusion, becoming the core device for testing the performance of first wall materials in laboratory simulation of fusion environments.

[0003] Lanthanum hexaboride (LaB6) has become an ideal choice for thermionic cathode materials due to its low work function, high melting point, and anti-poisoning characteristics. Currently, the mainstream LaB6 plasma sources mostly adopt a tungsten wire attachment heating structure: the tungsten wire is wound around one side of the LaB6 sheet, and the material is heated to an electron emission temperature of 1500 - 1800 °C through resistance heating. However, this traditional direct heating by tungsten wire will significantly increase the energy loss due to heat conduction loss, restricting the further improvement of electron emission performance; the local thermal stress caused by the asymmetric heating method is easily beyond the material's load-bearing limit, especially in larger-sized cathodes, which is likely to induce the propagation of microcracks, directly affecting the reliability and lifespan of the device. Summary of the Invention

[0004] The objective of the present invention is to provide a plasma generating device, which avoids the heat radiation loss of traditional indirect tungsten wire heating, avoids the problem of heat stress concentration in traditional bending structures, reduces the risk of material fragmentation, and further improves the overall lifespan of the plasma generating device.

[0005] To achieve the above objective, the present invention provides a plasma generating device, comprising: An anode part, the anode part includes a housing and an anode flange connected to each other. An ionization chamber and a plasma channel that communicate with each other are formed inside the housing. The plasma channel is provided at one end of the ionization chamber away from the anode flange for the plasma in the ionization chamber to move; A cathode part, the cathode part includes a cathode flange and two heating electrodes fixedly inserted through the cathode flange. The cathode flange is hermetically connected to the anode flange to form the ionization chamber. One ends of the two heating electrodes entering the ionization chamber are respectively connected to a spaced-apart first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet. The first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are connected by a graphite connection block. The cathode part further includes an air inlet part, and the air inlet part passes through the cathode flange to fill the ionization chamber with ionization gas.

[0006] Compared with the prior art, the plasma generating device according to an embodiment of the present invention has the following beneficial effects: The cathode flange, the anode flange and the housing are sealed to form an ionization cavity. The heating electrode of the cathode part energizes the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet to heat the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet. After the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are heated, electrons are emitted outward. The air inlet part fills the ionization cavity with ionization gas. The ionization gas in the ionization cavity intensively collides with the electrons emitted from the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet and is fully ionized into plasma. The cathode is connected to the heating electrode, the anode is grounded as a whole, and a pressure difference is formed between the cathode and the anode, so that the plasma moves toward the plasma channel of the anode. In the present application, the cathode directly connects the heating electrode to the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet. When the current flows through the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, it directly heats up through the Joule effect, avoiding the heat radiation loss of the traditional indirect heating of tungsten wire. At the same time, since the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are heated evenly as a whole, and the two lanthanum hexaboride sheets are thermally backed up to each other. When one of them causes electron emission attenuation due to local overheating, the other can quickly conduct heat through the graphite connection block for compensation, avoiding the problem of thermal stress concentration caused by the curved structure of the traditional single lanthanum hexaboride sheet, reducing the risk of material fragmentation, ensuring the reliability of the lanthanum hexaboride part, and further improving the overall life of the plasma generating device.

[0007] In the plasma generating device according to an embodiment of the present invention, both the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet include a first connection part, an ionization part and a second connection part connected in sequence. The first connection part is connected to the heating electrode, the second connection part is connected to the graphite connection block, and the ionization part is arranged to rotate along the length direction of the ionization cavity.

[0008] In the plasma generating device according to an embodiment of the present invention, the cathode part further includes a first high-temperature resistant connection block, a first conductive connection block, a second high-temperature resistant connection block and a second conductive connection block. The first lanthanum hexaboride sheet, the first high-temperature resistant connection block, the first conductive connection block and the heating electrode are connected in sequence. The second lanthanum hexaboride sheet, the second high-temperature resistant connection block, the second conductive connection block and the heating electrode are connected in sequence.

[0009] In the plasma generating device according to an embodiment of the present invention, the air inlet part includes an air inlet pipe passing through the cathode flange and the anode flange. The air inlet pipe extends in the ionization cavity and passes through the graphite connection block. The air outlet end of the air inlet pipe is located between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet.

[0010] In the plasma generating device according to an embodiment of the present invention, the part of the air inlet part extending into the ionization cavity is made of ceramic material.

[0011] In the plasma generating device according to an embodiment of the present invention, a ceramic cover body is sleeved outside the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, and an opening facing the plasma channel is formed in the ceramic cover body.

[0012] In the plasma generating device according to an embodiment of the present invention, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are detachably connected to the graphite connection block, and the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are also detachably connected to the heating electrode.

[0013] In the plasma generating device according to an embodiment of the present invention, the housing includes an inner sleeve and an outer sleeve connected to the anode flange. An ionization chamber is formed inside the inner sleeve, and a liquid cooling chamber is formed between the outer sleeve sleeved on the outer periphery of the inner sleeve and the inner sleeve. The liquid cooling chamber is arranged around the plasma channel and the ionization chamber; A liquid inlet and a liquid outlet communicating with the liquid cooling chamber are arranged on the outer sleeve, and both the liquid inlet and the liquid outlet are arranged towards the outside of the outer sleeve.

[0014] In the plasma generating device according to an embodiment of the present invention, the diameter of the plasma channel is smaller than the diameter of the ionization chamber.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic external structure diagram of the plasma generating device according to an embodiment of the present invention; Figure 2 is a schematic cathode part structure diagram of the plasma generating device according to an embodiment of the present invention; Figure 3 is a schematic anode part structure diagram of the plasma generating device according to an embodiment of the present invention; Figure 4 is a schematic internal structure diagram of the plasma generating device according to an embodiment of the present invention; Figure 5 is a schematic structure diagram of the first lanthanum hexaboride sheet of the plasma generating device according to an embodiment of the present invention; In the figure: 1 is the cathode part; 11 is the heating electrode; 12 is the cathode flange; 13 is the first lanthanum hexaboride sheet; 131 is the first connection part; 132 is the second connection part; 133 is the ionization part; 14 is the second lanthanum hexaboride sheet; 15 is the graphite connection block; 16 is the air inlet part; 17 is the first high-temperature resistant connection block; 18 is the first conductive connection block; 19 is the second high-temperature resistant connection block; 110 is the second conductive connection block; 111 is the ceramic cover; 2 is the anode part; 21 is the ionization chamber; 22 is the liquid cooling chamber; 23 is the liquid inlet; 24 is the liquid outlet; 25 is the housing; 251 is the inner sleeve; 252 is the outer sleeve; 26 is the anode flange; 27 is the plasma channel. Detailed implementation manners

[0017] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0018] In the description of the present invention, it should be understood that for the orientation description, such as up, down, front, back, left, right, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0019] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is more than two, and understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number. If the first and second are described only for the purpose of distinguishing technical features, they should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0020] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0021] As Figure 1 、 Figure 2 and Figure 4As shown in the figure, a plasma generating device according to a preferred embodiment of the present invention includes an anode part 2 and a cathode part 1. The anode part 2 includes a housing 25 and an anode flange 26 which are connected to each other. A plasma channel 27 and an ionization chamber 21 which communicate with each other are formed in the housing 25. The plasma channel 27 is arranged at one end of the ionization chamber 21 away from the anode flange 26. Among them, the housing 25 is a cylindrical metal housing and is grounded. The ionization chamber 21 needs to be evacuated before operation. Further, the anode flange 26 and the cathode flange 12 are connected through components such as a vacuum sealing gasket to form a closed ionization chamber 21 inside.

[0022] The cathode part 1 includes a cathode flange 12. The cathode part 1 includes two heating electrodes 11 and a first lanthanum hexaboride sheet 13 and a second lanthanum hexaboride sheet 14 which are respectively connected to the heating electrodes 11. The heating electrodes 11 are fixedly arranged through the cathode flange 12. One end of the heating electrode 11 is connected to a power supply outside the cathode flange 12, and the other end enters the ionization chamber 21 to be connected to the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. Both the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are located in the ionization chamber 21. The first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 can be heated up after being energized by the heating electrodes 11, emit electrons outward and ionize the gas in the ionization chamber 21. Further, the cathode part 1 further includes an air inlet part 16. The air inlet part 16 is located in the central area of the cathode flange 12 and extends into the ionization chamber 21 to the area where the lanthanum hexaboride part 31 is located. The air inlet part 16 penetrates through the cathode flange 12 to supply ionization gas into the ionization chamber 21.

[0023] When the present application is working, the cathode flange 12, the anode flange 26 and the housing 25 are sealed to form an ionization chamber 21. The heating electrode 11 of the cathode part 1 energizes the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 to heat the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. After the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are uniformly heated as a whole, electrons are emitted outward. The air inlet part 16 provides ionization gas to the ionization chamber 21. The ionization gas intensively collides with the electrons emitted by the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 and is fully ionized into plasma. The cathode is connected to the heating electrode 11, and the anode part 2 is grounded as a whole. During operation, a vacuum pump is provided outside the plasma channel to evacuate the entire ionization chamber 21 area, so as to form a pressure difference between the cathode part 1 and the anode part 2, and make the plasma move towards the plasma channel 27 of the anode part 2. The cathode of the present application directly connects the heating electrode 11 to both ends of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. When the current flows through lanthanum hexaboride, it directly heats up through the Joule effect, avoiding the heat radiation loss of the traditional indirect heating of tungsten wire. At the same time, since the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are uniformly heated as a whole, the problem of heat stress concentration of the traditional bending structure is avoided, the risk of material fragmentation is reduced, the reliability of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 is ensured, and the overall life of the plasma generating device is further improved.

[0024] The first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are connected by a graphite connection block 15. The first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are parallel to each other and arranged at intervals. One end of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 is connected to the graphite connection block 15. The graphite has strong electrical conductivity and can conduct heat evenly. The other ends of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are respectively connected to two heating electrodes 11. Through the parallel layout of the double lanthanum hexaboride sheets in the present application, compared with the layout of a single lanthanum hexaboride sheet, the effective emission area of the lanthanum hexaboride sheet is greatly increased. In addition, the two lanthanum hexaboride sheets are thermal backups for each other. When one of them has a decrease in electron emission due to local overheating, the other can quickly conduct heat through the graphite connection block 15 for compensation. When a single lanthanum hexaboride sheet fails, it needs to be replaced as a whole. However, the split design of the lanthanum hexaboride sheet also allows the damaged lanthanum hexaboride sheet to be replaced separately, and the undamaged lanthanum hexaboride sheet can still work normally without replacing the entire module, reducing the maintenance cost.

[0025] As Figure 5As shown, in some embodiments of the present invention, the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 both include a first connecting portion 131, a second connecting portion 132 and an ionizing portion 133, the first connecting portion 131, the ionizing portion 133 and the second connecting portion 132 are connected in sequence, the first connecting portion 131 and the second connecting portion 132 are connecting portions between the lanthanum hexaboride sheet and the outside world, and the ionizing portion 133 is a working portion of the lanthanum hexaboride sheet, which is used to emit electrons for ionization; the first connecting portion 131 includes a connecting portion for the heating electrode 11, and the second connecting portion 132 is connected to the graphite connecting block 15, the ionizing portion 133 is arranged between the first connecting portion 131 and the second connecting portion 132 and is arranged to rotate along the length direction of the ionization chamber 21 to form a spiral or wavy structure, which effectively increases the contact area between the heat conduction path and the ionized gas, enhances the local electric field strength of the lanthanum hexaboride sheet, and promotes the collision ionization rate of the electrons and the ionized gas. Furthermore, the flexible geometric configuration of the rotatably arranged ionization portion 133 can absorb thermal expansion deformation, reduce the risk of material breakage after heating, ensure the reliability of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14, and further improve the overall life of the plasma generating device.

[0026] In some embodiments of the present invention, a first high temperature resistant connecting block 17 and a first conductive connecting block 18 electrically connected to each other are sequentially arranged between the first lanthanum hexaboride sheet 13 and the heating electrode 11, and the first lanthanum hexaboride sheet 13, the first high temperature resistant connecting block 17, the first conductive connecting block 18 and the heating electrode 11 are sequentially connected; a second high temperature resistant connecting block 19 and a second conductive connecting block 110 electrically connected to each other are sequentially arranged between the second lanthanum hexaboride sheet 14 and the heating electrode 11, and the second lanthanum hexaboride sheet 14, the second high temperature resistant connecting block 19, the second conductive connecting block 110 and the heating electrode 11 are sequentially connected; wherein, the first high temperature resistant connecting block 17 and the second high temperature resistant connecting block 19 are centrally symmetrically arranged, the first high temperature resistant connecting block 17 and the second high temperature resistant connecting block 19 are made of materials such as molybdenum or tungsten to withstand the high temperature after the lanthanum hexaboride is heated, the first conductive connecting block 18 and the second conductive connecting block 110 are made of the same conductive material, and the above components are all connected by threads, which are stably and firmly fixed.

[0027] In some embodiments of the present invention, the air inlet 16 includes an air inlet pipe that is inserted through the cathode flange and the anode flange 26. The centers of the cathode flange 12 and the anode flange 26 are provided with holes that match the size of the air inlet pipe and are sealed to prevent air leakage at the connection between the air inlet pipe and the cathode flange 12 and the anode flange 26; the air inlet pipe extends in the ionization chamber 21 and is inserted through the graphite connection block 15. The air outlet end of the air inlet pipe is located between the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. After the air inlet pipe extends out of the graphite connection block 15, the air outlet end is located between the two lanthanum hexaboride sheets, forming a core area of bipolar upper and lower ionization. This design allows ionized gas (such as argon) to be directly injected into the cathode area with high electron density, and the collision ionization efficiency is significantly improved. In addition, since the air outlet end is located between the two lanthanum hexaboride sheets, the flow of the ionized gas can be used to take away the Joule heat on the surface of the lanthanum hexaboride sheet, providing a certain heat dissipation capacity and further improving the temperature gradient on the surface of the lanthanum hexaboride sheet.

[0028] Preferably, the portion of the air inlet 16 located in the ionization chamber 21 is made of ceramic material. The ceramic material has a low linear expansion coefficient, and exhibits excellent heat resistance and corrosion resistance in a fluorine-containing plasma environment, can resist chemical corrosion of fluorine-containing gases, avoid the problem of the traditional aluminum anodized film falling off, and increase the life of the air inlet pipe; the high hardness and low sputtering rate characteristics of the ceramic can also reduce the physical erosion of the high-energy ions on the inside of the air inlet pipe.

[0029] In some embodiments of the present invention, a ceramic cover 111 is provided on the outer side of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. The ceramic cover 111 has an opening facing the plasma channel 27. The setting of the ceramic cover 111 enables the first lanthanum hexaboride sheet 13, the second lanthanum hexaboride sheet 14 and the outlet end of the air inlet pipe to form a relatively independent space. The closed space formed by the ceramic cover 111 can confine the ionized gas to the core area of the lanthanum hexaboride sheet and the outlet end of the air inlet pipe, and the gas residence time is prolonged, so that the ionized gas can collide with the electrons emitted by the lanthanum hexaboride sheet in a more concentrated manner and be fully ionized into plasma. The setting of the opening enables the ionized plasma to leave the ceramic cover area through the opening and reach the plasma channel 27.

[0030] In some embodiments of the present invention, the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are detachably connected to the graphite connection block 15, and the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are also detachably connected to the heating electrode 11. Specifically, the detachable connection is a bolt connection, which can be quickly replaced when replacement is required. The detachable structure supports flexible adjustment of the size of the lanthanum hexaboride sheet, so that the lanthanum hexaboride sheet is not limited by the diameter of the vacuum chamber, but is extended or shortened in the axial dimension of the vacuum chamber, effectively increasing the electron emission area of lanthanum hexaboride, improving the gas ionization rate and thus improving the plasma density, and meeting the different area plasma requirements of different nuclear fusion devices.

[0031] As Figure 3 shown, in some embodiments of the present invention, the housing 25 includes an inner sleeve 251 connected to the anode flange 26 and an outer sleeve 252. The ionization chamber is formed within the inner sleeve 251. The outer sleeve 252 is sleeved around the outer periphery of the inner sleeve 251, and a liquid cooling chamber 22 is formed between the outer sleeve 252 and the inner sleeve 251. The liquid cooling chamber 22 surrounds the plasma channel 27 and the ionization chamber 21 to reduce the temperatures of the ionization chamber 21 and the plasma channel 27. During the ionization operation, there are a large number of high-temperature plasmas in this area, which will generate a large amount of thermal radiation on the outer wall of the housing 25. Through the surrounding layout, the liquid cooling chamber 22 is in direct contact with the outer wall of the plasma channel 27, and uses the high thermal conductivity of the liquid (such as water or liquid nitrogen) to quickly absorb the Joule heat generated by the plasma channel 27, effectively preventing thermal damage to the housing 25 material caused by high temperatures.

[0032] In some embodiments of the present invention, the outer sleeve 252 is provided with a liquid inlet 23 and a liquid outlet 24 communicating with the liquid cooling chamber 22. The liquid inlet 23 and the liquid outlet 24 are respectively used to supply and discharge the refrigerant to the liquid cooling chamber 22, ensuring the circulation of the refrigerant and the high heat exchange efficiency of the liquid cooling chamber 22. The liquid inlet 23 and the liquid outlet 24 are both arranged towards the outside of the outer sleeve 252.

[0033] In some embodiments of the present invention, during operation, the entire plasma generating device is arranged in the central part of the coil. The plasma ionized at the ionization chamber 21 enters the plasma channel and is constrained by the magnetic field into a beam with a smaller diameter and moves along the magnetic field lines. A pump set is provided at a position far from the plasma channel 27 to evacuate the entire chamber, creating a pressure difference between the plasma channel 27 and the ionization chamber 21, which is beneficial to promoting the ionized plasma to enter the plasma channel 27, accelerating the flow rate of the plasma, and facilitating the high-speed ejection of the plasma.

[0034] In some embodiments of the present invention, both the cathode flange 12 and the anode flange 26 are standard CF flanges. The cathode flange 12 and the anode flange 26 are connected by screws and then sealed with a copper gasket to ensure airtightness. Moreover, the anode flange 26 is hermetically welded to the housing 25 to provide the vacuum environment required for the operation of the plasma generating device, ensuring that only the ionized gas exists in the ionization chamber 21 during the reionization process, making the ionization process safe and reliable.

[0035] The working process of the present invention is as follows: The cathode flange 12, the anode flange 26 and the housing 25 are sealed to form an ionization chamber 21. The heating electrode 11 of the cathode part 1 energizes the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 to heat the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. After the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are heated, they emit electrons outward. The air inlet part 16 then fills the ionization chamber 21 with ionization gas. The ionization gas in the ionization chamber 21 concentrates and collides with the electrons emitted by the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14, and is fully ionized into plasma; the cathode part 1 is connected to a heating power supply, the anode part 2 is grounded as a whole, and the vacuum pump group outside the plasma channel 27 evacuates the ionization chamber 21 to form a pressure difference between the cathode and the anode, so that the plasma moves towards the plasma channel 27 of the anode.

[0036] In summary, the embodiment of the present invention provides a plasma generating device, which directly connects the heating electrode 11 with the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. When the current flows through the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14, it directly heats up through the Joule effect, avoiding the heat radiation loss of the traditional tungsten wire indirect heating; at the same time, since the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are uniformly heated as a whole, and the two lanthanum hexaboride sheets are thermally backed up to each other. When one of them causes electron emission attenuation due to local overheating, the other can quickly conduct heat through the graphite connection block 15 for compensation, avoiding the problem of thermal stress concentration caused by the curved structure of the traditional single lanthanum hexaboride sheet, reducing the risk of material fragmentation, ensuring the reliability of the lanthanum hexaboride part, and further improving the overall life of the plasma generating device.

[0037] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and replacements can be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. A plasma generating device, characterized in that, Comprising: An anode part, the anode part includes a housing and an anode flange connected to each other. An ionization chamber and a plasma channel communicating with each other are formed in the housing. The plasma channel is arranged at one end of the ionization chamber away from the anode flange for the plasma in the ionization chamber to move; A cathode part, the cathode part includes a cathode flange and two heating electrodes fixedly arranged through the cathode flange. The cathode flange is hermetically connected to the anode flange to form the ionization chamber. One ends of the two heating electrodes entering the ionization chamber are respectively connected with a spaced first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet. The first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are connected by a graphite connection block. The cathode part further includes an air inlet part, and the air inlet part penetrates through the cathode flange to fill the ionization chamber with ionization gas.

2. The plasma generating device according to claim 1, characterized in that: Both the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet include a first connection part, an ionization part and a second connection part connected in sequence. The first connection part is connected to the heating electrode, the second connection part is connected to the graphite connection block, and the ionization part is arranged in a revolving manner along the length direction of the ionization chamber.

3. The plasma generating device according to claim 1, wherein: The cathode part further includes a first high-temperature resistant connection block, a first conductive connection block, a second high-temperature resistant connection block and a second conductive connection block. The first lanthanum hexaboride sheet, the first high-temperature resistant connection block, the first conductive connection block and the heating electrode are connected in sequence. The second lanthanum hexaboride sheet, the second high-temperature resistant connection block, the second conductive connection block and the heating electrode are connected in sequence.

4. The plasma generating device according to claim 1, characterized in that: The air inlet part includes an air inlet pipe penetrating through the cathode flange and the anode flange. The air inlet pipe extends in the ionization chamber and penetrates through the graphite connection block. The air outlet end of the air inlet pipe is located between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet.

5. The plasma generating device according to claim 1, characterized in that: The part of the air inlet part extending into the ionization chamber is made of ceramic material.

6. The plasma generating device according to claim 1, characterized in that: Ceramic cover bodies are sleeved outside the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, and the ceramic cover bodies are provided with openings facing the plasma channel.

7. The plasma generating device according to claim 2, wherein: The connection between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet and the graphite connection block is detachable, and the connection between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet and the heating electrode is also detachable.

8. The plasma generating device according to claim 1, characterized in that: The housing includes an inner sleeve connected to the anode flange and an outer sleeve. The ionization chamber is formed in the inner sleeve. The outer sleeve is sleeved outside the inner sleeve and a liquid cooling chamber is formed between the outer sleeve and the inner sleeve. The liquid cooling chamber is arranged around the plasma channel and the ionization chamber; The outer sleeve is provided with a liquid inlet and a liquid outlet communicating with the liquid cooling chamber, and both the liquid inlet and the liquid outlet are arranged facing the outside of the outer sleeve.

9. The plasma generating device according to claim 1, wherein: A pump set is arranged on one side of the plasma channel away from the cathode part to evacuate the ionization chamber.

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