Plasma generator

Abstract

The present invention relates to the field of plasma source technology, and discloses a plasma generator comprising: an anode portion, the anode portion comprising an interconnected housing and an anode flange, wherein an interconnected ionization chamber and a plasma channel are formed within the housing; a cathode portion, the cathode portion comprising a cathode flange and two heating electrodes, wherein the two heating electrodes are respectively connected to a first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet spaced apart, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet being connected by a graphite connecting block; and an air inlet portion for filling the ionization chamber with ionized gas. The cathode of the present application utilizes heating electrodes directly connected to both ends of the lanthanum hexaboride portion, resulting in uniform heating of the entire lanthanum hexaboride portion, thereby avoiding the thermal stress concentration problem of conventional curved structures, reducing the risk of material fracture, ensuring the reliability of the lanthanum hexaboride portion, and further improving the overall life of the plasma generator.

Description

Technical Field

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

[0002] Hot cathode plasma sources are widely used in industry due to their stable electron emission and excellent plasma uniformity. Compared to arc plasma sources (high density but poor stability) and ECR plasma sources (inadequate density), hot cathode plasma sources offer a balanced density and stability when simulating the divertor environment of nuclear fusion, making them a core device for testing first-wall material properties in laboratory simulations of fusion environments.

[0003] Lanthanum hexaboride (LaB6) is an ideal choice for hot cathode materials due to its low work function, high melting point, and resistance to poisoning. Current mainstream LaB6 plasma sources mostly use a tungsten filament-attached heating structure: a tungsten filament is wrapped around one side of a LaB6 sheet, and resistive heating is used to raise the material to an electron emission temperature of 1500-1800°C. However, this traditional direct heating method using a tungsten filament significantly increases energy loss due to thermal conduction losses, limiting further improvements in electron emission performance. Furthermore, the local thermal stress induced by asymmetric heating can easily exceed the material's bearing capacity, inducing microcrack propagation, especially in larger cathodes, which directly affects device reliability and lifespan. Summary of the Invention

[0004] The purpose of the present invention is to provide a plasma generator that avoids the heat radiation loss of traditional tungsten filament indirect heating, avoids the thermal stress concentration problem of traditional curved structures, reduces the risk of material fragmentation, and further improves the overall life of the plasma generator.

[0005] In order to achieve the above object, the present invention provides a plasma generating device, comprising:

[0006] an anode portion, the anode portion comprising a housing and an anode flange connected to each other, wherein an ionization chamber and a plasma channel connected to each other are formed in the housing, and the plasma channel is provided at an end of the ionization chamber away from the anode flange for movement of plasma in the ionization chamber;

[0007] The cathode part includes a cathode flange and two heating electrodes fixed to the cathode flange. The cathode flange is sealed and connected to the anode flange to form the ionization chamber. The two heating electrodes enter one end of the ionization chamber and are respectively connected to a first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet that are spaced apart. The first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are connected by a graphite connecting block. The cathode part also includes an air inlet, which is passed through the cathode flange to fill the ionization chamber with ionized gas.

[0008] Compared with the prior art, a plasma generating device according to an embodiment of the present invention has the following advantages: a cathode flange, an anode flange, and a shell are sealed to form an ionization chamber; a heating electrode at the cathode portion energizes a first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet to heat the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, and the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet emit electrons after being heated; an air inlet portion fills the ionization chamber with ionized gas, and the ionized gas in the ionization chamber collides with the electrons emitted by the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, thereby being 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, causing the plasma to move toward the plasma channel of the anode. The cathode of the present application uses a heating electrode to be directly connected to the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet. When current flows through the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, the temperature is directly increased by the Joule effect, avoiding the heat radiation loss of traditional tungsten filament indirect heating. At the same time, since the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are uniformly heated as a whole, and the two lanthanum hexaboride sheets serve as thermal backups for each other, when one of the sheets causes electron emission to decay due to local overheating, the other sheet can compensate by quickly conducting heat through the graphite connecting block, avoiding the thermal stress concentration problem caused by the bending structure of the traditional single-piece lanthanum hexaboride sheet, reducing the risk of material fragmentation, ensuring the reliability of the lanthanum hexaboride section, and further improving the overall life of the plasma generating device.

[0009] In the plasma generating device of an embodiment of the present invention, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet each include a first connecting portion, an ionization portion, and a second connecting portion connected in sequence, the first connecting portion being connected to the heating electrode, the second connecting portion being connected to the graphite connecting block, and the ionization portion being arranged to rotate along the length direction of the ionization chamber.

[0010] In the plasma generating device of an embodiment of the present invention, the cathode portion further includes a first high-temperature resistant connecting block, a first conductive connecting block, a second high-temperature resistant connecting block, and a second conductive connecting block; the first lanthanum hexaboride sheet, the first high-temperature resistant connecting block, the first conductive connecting block, and the heating electrode are connected in sequence; and the second lanthanum hexaboride sheet, the second high-temperature resistant connecting block, the second conductive connecting block, and the heating electrode are connected in sequence.

[0011] In the plasma generating device of an embodiment of the present invention, the air inlet portion includes an air inlet pipe passing through the cathode flange and the anode flange, the air inlet pipe extends in the ionization chamber and passes through the graphite connecting block, and the air outlet end of the air inlet pipe is located between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet.

[0012] In the plasma generating device according to the embodiment of the present invention, the portion of the air inlet extending into the ionization chamber is made of ceramic material.

[0013] In the plasma generating device of the embodiment of the present invention, a ceramic cover is provided on the outer side of the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet, and the ceramic cover has an opening facing the plasma channel.

[0014] In the plasma generating device of the embodiment of the present invention, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are detachably connected to the graphite connecting block, and the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are also detachably connected to the heating electrode.

[0015] In the plasma generating device of an embodiment of the present invention, the housing includes an inner sleeve and an outer sleeve connected to the anode flange, the ionization chamber is formed in the inner sleeve, the outer sleeve is arranged on the outer periphery of the inner sleeve and a liquid cooling chamber is formed between the outer sleeve and the inner sleeve, and the liquid cooling chamber is arranged around the plasma channel and the ionization chamber;

[0016] The outer jacket is provided with a liquid inlet and a liquid outlet communicating with the liquid cooling cavity, and the liquid inlet and the liquid outlet are both arranged toward the outside of the outer jacket.

[0017] In the plasma generating device according to the embodiment of the present invention, the diameter of the plasma channel is smaller than the diameter of the ionization chamber.

[0018] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a schematic diagram of the external structure of a plasma generating device according to an embodiment of the present invention;

[0020] Figure 2 2. It is a schematic structural diagram of the cathode portion of a plasma generating device according to an embodiment of the present invention;

[0021] Figure 3 1 is a schematic structural diagram of the anode portion of a plasma generating device according to an embodiment of the present invention;

[0022] Figure 4 1 is a schematic diagram of the internal structure of a plasma generating device according to an embodiment of the present invention;

[0023] Figure 5 2 is a schematic structural diagram of a first lanthanum hexaboride sheet of a plasma generating device according to an embodiment of the present invention;

[0024] In the figure, 1. cathode part; 11. heating electrode; 12. cathode flange; 13. first lanthanum hexaboride sheet; 131. first connecting part; 132. second connecting part; 133. ionization part; 14. second lanthanum hexaboride sheet; 15. graphite connecting block; 16. air inlet; 17. first high-temperature resistant connecting block; 18. first conductive connecting block; 19. second high-temperature resistant connecting block; 110. second conductive connecting block; 111. ceramic cover; 2. anode part; 21. ionization chamber; 22. liquid cooling chamber; 23. liquid inlet; 24. liquid outlet; 25. shell; 251. inner sleeve; 252. outer sleeve; 26. anode flange; 27. plasma channel. DETAILED DESCRIPTION

[0025] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0026] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0027] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] like Figure 1 、 Figure 2 and Figure 4As shown, a plasma generating device according to a preferred embodiment of the present invention includes an anode portion 2 and a cathode portion 1. The anode portion 2 includes a shell 25 and an anode flange 26 connected to each other. A plasma channel 27 and an ionization chamber 21 are formed in the shell 25. The plasma channel 27 is arranged at one end of the ionization chamber 21 away from the anode flange 26. The shell 25 is a cylindrical metal shell and is grounded. The ionization chamber 21 needs to be evacuated before operation. Furthermore, the anode flange 26 is connected to the cathode flange 12 by components such as a vacuum sealing gasket to form a closed ionization chamber 21 inside.

[0030] 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 respectively connected to the heating electrodes 11, the heating electrode 11 is passed through and fixed to the cathode flange 12, one end of the heating electrode 11 is connected to the power supply outside the cathode flange 12, and the other end enters the ionization chamber 21 to connect the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14; the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are both located in the ionization chamber 21, and the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 can be heated by energizing the heating electrode 11, emitting electrons outward and ionizing the gas in the ionization chamber 21; further, the cathode part 1 also includes an air inlet 16, which 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, and the air inlet 16 is passed through the cathode flange 12 to provide ionized gas to the ionization chamber 21.

[0031] When the present application is working, the cathode flange 12, the anode flange 26 and the shell 25 are sealed to form an ionization chamber 21, and 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, they emit electrons outward, and the air inlet 16 provides ionized gas to the ionization chamber 21. The ionized gas 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. When working, a vacuum pump is provided outside the plasma channel to evacuate the entire ionization chamber 21 area to form a pressure difference between the cathode part 1 and the anode part 2, so that the plasma moves toward the plasma channel 27 of the anode part 2. The cathode of the present application uses a heating electrode 11 that is directly connected to both ends of the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14. When current flows through the lanthanum hexaboride, it is directly heated by the Joule effect, avoiding the heat radiation loss of traditional tungsten filament indirect heating; at the same time, since the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are heated uniformly as a whole, the thermal stress concentration problem of the traditional curved 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.

[0032] The first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 are connected by a graphite connecting 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 connecting block 15. 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. The present application greatly improves the effective emission area of ​​the lanthanum hexaboride sheet by arranging two lanthanum hexaboride sheets in parallel compared to the layout of a single lanthanum hexaboride sheet. In addition, the two lanthanum hexaboride sheets serve as thermal backups for each other. When one of the sheets causes electron emission to decay due to local overheating, the other sheet can compensate by quickly conducting heat through the graphite connecting block 15. When a single-sheet lanthanum hexaboride sheet fails, it needs to be replaced as a whole. The split design of the lanthanum hexaboride sheet also allows the damaged lanthanum hexaboride sheet to be replaced separately, and the lanthanum hexaboride sheet that has not failed can still work normally without replacing the entire module, thereby reducing maintenance costs.

[0033] like Figure 5As shown, in some embodiments of the present invention, the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 each include a first connecting portion 131, a second connecting portion 132 and an ionization portion 133. The first connecting portion 131, the ionization 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 of the lanthanum hexaboride sheet with the outside world, and the ionization portion 133 is a working portion of the lanthanum hexaboride sheet for emitting electrons for ionization. The first connecting portion 131 includes a portion connected to the heating electrode 11, and the second connecting portion 132 is connected to the graphite connecting block 15. The ionization portion 133 is disposed 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 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 fragmentation 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.

[0034] 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 connected in sequence; 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 connected in sequence; wherein, the first high-temperature resistant connecting block 17 and the second high-temperature resistant connecting block 19 are centrally symmetrically arranged, and 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, and 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 fixed stably and securely.

[0035] In some embodiments of the present invention, the air inlet portion 16 includes an air inlet pipe extending through the cathode flange 12 and the anode flange 26. The cathode flange 12 and the anode flange 26 are centrally provided with holes sized to match the air inlet pipe and sealed to prevent leakage at the connections between the air inlet pipe and the cathode flange 12 and the anode flange 26. The air inlet pipe extends within the ionization chamber 21 and extends through the graphite connecting block 15. The air outlet of the air inlet pipe is located between the first and second lanthanum hexaboride sheets 13 and 14. After extending through the graphite connecting block 15, the air outlet of the air inlet pipe is located between the two lanthanum hexaboride sheets, forming the core region for bipolar upper and lower ionization. This design allows ionized gas (such as argon) to be directly injected into the high electron density cathode region, significantly improving the impact ionization efficiency. Furthermore, since the air outlet is located between the two lanthanum hexaboride sheets, the flow of the ionized gas can be used to remove Joule heat from the surfaces of the lanthanum hexaboride sheets, providing a certain degree of heat dissipation capacity and further improving the temperature gradient on the surfaces of the lanthanum hexaboride sheets.

[0036] Preferably, the portion of the air intake 16 located within the ionization chamber 21 is made of ceramic. Ceramic has a low coefficient of linear expansion and exhibits excellent heat and corrosion resistance in a fluorine-containing plasma environment. It resists chemical corrosion from fluorine-containing gases, avoids the shedding of the anodized film on traditional aluminum, and increases the life of the intake pipe. The high hardness and low sputtering rate of ceramic also reduce physical erosion of the interior of the intake pipe by high-energy ions.

[0037] 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.

[0038] 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 connecting 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 needed. 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. Instead, the lanthanum hexaboride sheet can be extended or shortened in the axial dimension of the vacuum chamber, effectively increasing the electron emission area of ​​the lanthanum hexaboride, improving the gas ionization rate and thus the plasma density, meeting the different area plasma requirements of different nuclear fusion devices.

[0039] like Figure 3 As shown, in some embodiments of the present invention, the housing 25 includes an inner sleeve 251 and an outer sleeve 252 connected to the anode flange 26. The inner sleeve 251 forms the ionization chamber. The outer sleeve 252 is disposed around the outer periphery of the inner sleeve 251, and a liquid cooling chamber 22 is formed between the inner sleeve 251 and the outer sleeve 252. The liquid cooling chamber 22 surrounds the plasma channel 27 and the ionization chamber 21 to reduce the temperature of the ionization chamber 21 and the plasma channel 27. During ionization operation, a large amount of high-temperature plasma is present in this region, generating a large amount of heat radiation to the outer wall of the housing 25. The liquid cooling chamber 22, through its surrounding layout, directly contacts the outer wall of the plasma channel 27. The high thermal conductivity of the liquid (such as water or liquid nitrogen) is used to quickly absorb the Joule heat generated by the plasma channel 27, effectively preventing thermal damage to the housing 25 material caused by high temperature.

[0040] In some embodiments of the present invention, the outer jacket 252 is provided with a liquid inlet 23 and a liquid outlet 24 connected to the liquid cooling chamber 22. The liquid inlet 23 and the liquid outlet 24 are respectively used to provide and discharge refrigerant to the liquid cooling chamber 22, thereby ensuring the circulation of the refrigerant and the efficient heat exchange efficiency of the liquid cooling chamber 22; the liquid inlet 23 and the liquid outlet 24 are both arranged toward the outside of the outer jacket 252.

[0041] In some embodiments of the present invention, during operation, the entire plasma generating device is arranged at the center part of the coil. After the plasma ionized at the ionization chamber 21 enters the plasma channel, it is constrained by the magnetic field into a beam with a smaller diameter and moves along the direction of the magnetic field lines. A pump group is provided away from the plasma channel 27 to evacuate the entire chamber, so that a pressure difference is formed between the plasma channel 27 and the ionization chamber 21, which is conducive to pushing the ionized plasma into the plasma channel 27, accelerating the flow rate of the plasma, and facilitating the high-speed emission of the plasma.

[0042] In some embodiments of the present invention, the cathode flange 12 and the anode flange 26 are both standard CF flanges, which are connected by screws and then sealed by copper gaskets to ensure airtightness; and the anode flange 26 and the shell 25 are sealed and welded to provide the vacuum environment required for the operation of the plasma generating device, ensuring that only ionized gas exists in the ionization chamber 21 during the reionization process, making the ionization process safe and reliable.

[0043] The working process of the present invention is as follows: the cathode flange 12, the anode flange 26 and the shell 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, and the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14 emit electrons outward after being heated, and the air inlet part 16 fills the ionization chamber 21 with ionized gas, and the ionized gas in the ionization chamber 21 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 toward the plasma channel 27 of the anode.

[0044] In summary, an embodiment of the present invention provides a plasma generating device, which uses a heating electrode 11 to be directly connected to a first lanthanum hexaboride sheet 13 and a second lanthanum hexaboride sheet 14. When current flows through the first lanthanum hexaboride sheet 13 and the second lanthanum hexaboride sheet 14, the temperature is directly increased by the Joule effect, thereby avoiding the heat radiation loss of traditional tungsten filament 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 serve as thermal backups for each other, when one of the sheets causes electron emission to decay due to local overheating, the other sheet can compensate by quickly conducting heat through the graphite connecting block 15, thereby avoiding the thermal stress concentration problem caused by the bending structure of the traditional single-piece lanthanum hexaboride sheet, reducing the risk of material fragmentation, ensuring the reliability of the lanthanum hexaboride sheet, and further improving the overall life of the plasma generating device.

[0045] 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 plasma generating device, characterized in that: include: an anode portion, the anode portion comprising a housing and an anode flange connected to each other, wherein an ionization chamber and a plasma channel connected to each other are formed in the housing, and the plasma channel is provided at an end of the ionization chamber away from the anode flange for movement of plasma in the ionization chamber; A cathode portion, comprising a cathode flange and two heating electrodes fixedly mounted on the cathode flange, the cathode flange being sealed and connected to the anode flange to form the ionization chamber, the two heating electrodes entering one end of the ionization chamber and respectively connected to a first lanthanum hexaboride sheet and a second lanthanum hexaboride sheet spaced apart, the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet being connected via a graphite connecting block, the cathode portion further comprising an air inlet, the air inlet being mounted on the cathode flange to supply ionized gas to the ionization chamber; The first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet each include a first connecting portion, an ionization portion, and a second connecting portion connected in sequence, wherein the first connecting portion is connected to the heating electrode, the second connecting portion is connected to the graphite connecting block, and the ionization portion is rotated along the length direction of the ionization chamber.

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

3. The plasma generating device according to claim 1, wherein: The air inlet portion includes an air inlet pipe passing through the cathode flange and the anode flange. The air inlet pipe extends in the ionization chamber and passes through the graphite connecting block. The air outlet end of the air inlet pipe is located between the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet.

4. The plasma generating device according to claim 1, wherein: The portion of the air inlet extending into the ionization chamber is made of ceramic material.

5. The plasma generating device according to claim 1, wherein: A ceramic cover is provided on the outer sides of the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet. The ceramic cover has an opening facing the plasma channel.

6. The plasma generating device according to claim 1, wherein: The first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are detachably connected to the graphite connecting block, and the first lanthanum hexaboride sheet and the second lanthanum hexaboride sheet are also detachably connected to the heating electrode.

7. The plasma generating device according to claim 1, wherein: The housing includes an inner sleeve and an outer sleeve connected to the anode flange, the inner sleeve forms the ionization chamber, the outer sleeve is arranged on the outer periphery of the inner sleeve and a liquid cooling chamber is formed between the outer sleeve and the inner sleeve, and the liquid cooling chamber is arranged around the plasma channel and the ionization chamber; The outer jacket is provided with a liquid inlet and a liquid outlet communicating with the liquid cooling cavity, and the liquid inlet and the liquid outlet are both arranged toward the outside of the outer jacket.

8. The plasma generating device according to claim 1, wherein: A pump group is provided on a side of the plasma channel away from the cathode portion to evacuate the ionization chamber.

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