阅读说明：本技术 一种大尺寸高发射电流密度的等离子体源 (Large-size high-emission-current-density plasma source ) 是由 孟凡卫 胡广海 孔德峰 张小辉 叶扬 赵志豪 董期龙 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种大尺寸高发射电流密度的等离子体源,包括阳极、阴极、直角连接器、固定法兰、真空密封组件、开槽铜棒,所述阳极、阴极通过直角连接器与开槽铜棒相连,所述开槽铜棒与固定法兰通过真空密封组件进行密封,所述开槽铜棒侧面走循环水冷和内部导电,所述阳极与阴极工作环境为真空、有磁场,阴极与阳极平行放置在真空环境中,阴极与阳极在直流或脉冲条件下进行放电,在阳极与阴极之间会有电流通道产生,且阴、阳极间产生的电流较高,产生等离子体参数较高,能实现大间距放电。可以用来研究磁场重联、等离子体不稳定性、漂移波湍流、带状流等基础物理问题,还可以作为紧凑环背景等离子体源为以后紧凑环注入EAST装置打下基础。(The invention discloses a large-size high-emission current density plasma source which comprises an anode, a cathode, a right-angle connector, a fixing flange, a vacuum sealing assembly and a slotted copper bar, wherein the anode and the cathode are connected with the slotted copper bar through the right-angle connector, the slotted copper bar and the fixing flange are sealed through the vacuum sealing assembly, the side surface of the slotted copper bar is circulated with water cooling and is internally conductive, the working environments of the anode and the cathode are vacuum and have a magnetic field, the cathode and the anode are placed in the vacuum environment in parallel, the cathode and the anode discharge under the direct current or pulse condition, a current channel is generated between the anode and the cathode, the current generated between the cathode and the anode is higher, the generated plasma parameters are higher, and large-interval discharge can be realized. The method can be used for researching basic physical problems of magnetic field reconnection, plasma instability, drift wave turbulence, ribbon flow and the like, and can also be used as a compact ring background plasma source to lay a foundation for a compact ring injection EAST device.)

1. A large-size high emission current density plasma source, comprising: the anode comprises an anode net (11) and an anode fixing ring, the anode is connected with the slotted copper rod (1) through the right-angle connector (8), the cathode comprises a cathode emitter (15), a cathode emitter conducting ring (24), a heat source (28), a heat reflection plate, a heat reflection cup (14), a heat source fixer (29), a heat reflection cup fixing ring (13) and an insulating material, the cathode is connected with the slotted copper rod (1) through the right-angle connector (8), the slotted copper rod (1) and the flange are sealed through the vacuum sealing assembly, circulating water cooling and internal conduction are carried out on the side surface of the slotted copper rod (1), the anode and the cathode working environment are vacuum and have a magnetic field, and the cathode and the anode are placed in the vacuum environment in parallel, the spacing is adjustable.

2. The large-scale high emission current density plasma source of claim 1, wherein: the positive pole includes positive pole net (11), positive pole upper fixed ring (9), positive pole lower fixed ring (22), and positive pole upper fixed ring (9), positive pole lower fixed ring (22) one side respectively the recess is used for placing positive pole net (11), and it is fixed to flare-out to pass through positive pole upper fixed ring screw (10) with positive pole net (11).

3. The large-scale high emission current density plasma source of claim 1, wherein: the vacuum sealing assembly comprises an upper sealing element (20), a lower sealing element (3), an O-shaped ring (21), a sealing nut (4), a copper bar fixing bolt (6), a sealing flange (5) and an insulating material (7), wherein the upper sealing element (20), the lower sealing element (3), the O-shaped ring (21) and the insulating material (7) are all fixed on the sealing flange (5) through the sealing nut (4) and the copper bar fixing bolt (6), and the vacuum sealing assembly is prevented from leaking gas and being damaged by the grooved copper bar (1).

4. A large-size high emission current density plasma source as claimed in claim 1 or 3, wherein: the anode and the cathode work in a vacuum chamber, the anode and the cathode are led out of the vacuum chamber from the inside of the vacuum chamber through the slotted copper bar (1) and the sealing flange (5), and the heat source electrode (35) is also led out of the vacuum chamber through the slotted copper bar (1).

5. The large-scale high emission current density plasma source of claim 1, wherein: the side surface of the slotted copper rod (1) is provided with a water-cooling inlet (2) and a water-cooling outlet (19), and high current can pass through the slotted copper rod (1) in the experimental process, so that heat is generated for cooling; the grooved sealing strip (18) and the groove are polished after brazing.

6. The large-scale high emission current density plasma source of claim 1, wherein: the cathode emitter (15) is made of lanthanum hexaboride and is located between the graphite gasket (23) and the graphite heat conducting sheet (25), the cathode emitter (15) is prevented from reacting with refractory metal at high temperature, the cathode emitter (15) is uniformly heated, the conducting ring (24) is arranged around the cathode emitter (15), the electrical connection of the cathode emitter (15) is guaranteed, and the cathode emitter (15) is protected from being broken due to thermal expansion.

7. The large-scale high emission current density plasma source of claim 6, wherein: a high-temperature insulating material (26) is arranged below the graphite heat conducting sheet (25), a heat source (28) and a heat source fixer (29) are arranged below the high-temperature insulating material (26), and the heat source (28) needs a direct-current power supply for heating.

8. The large-scale high emission current density plasma source of claim 7, wherein: the heat source (28) is in a snake shape, heat source screw holes (27) are respectively designed at two ends of the heat source (28), two ends of the heat source (28) are fixed on the heat source electrode (35) through the heat source screw holes (27), a circle of the heat source electrode (35) is also provided with a ceramic insulating material (34) to prevent the heat source electrode (35) from contacting with the heat reflection plate, the heat source electrode (35) is fixed on a stainless steel heat source leading-out electrode (36), the stainless steel heat source leading-out electrode (36) is connected on the slotted copper rod (1) through a lead wire to be led out, and the heat source fixer (29) is designed to have grooves on two sides and be made of a ceramic material according to the shape of the heat source to play roles in supporting the heat source (28) and insulating.

9. A large-size high emission current density plasma source as claimed in claim 6, 7 or 8 wherein: in order to improve the heat radiation utilization rate, three layers of heat reflecting plates are arranged below the heat source fixer (29) and used for reflecting the heat radiated backwards by the heat source (28) so as to enable the heat to return to the cathode emitter (15), wherein the three layers of heat reflecting plates are respectively a first heat reflecting plate (30), a second heat reflecting plate (31) and a third heat reflecting plate (32), and 8 identical heat reflecting plate connecting upright columns (37) are arranged in the middle of each layer of heat reflecting plate.

10. A large-size high emission current density plasma source as claimed in claim 6, 7, 8 or 9 wherein: the heat around the cathode emitter (15) is reflected by the heat reflection cup (14), meanwhile, a heat reflection cup cover plate (33) is arranged at the bottom of the heat reflection cup (14), and the heat reflection plate, the heat source (28), the heat source fixer (29), the cathode emitter (15), the high-temperature insulating material (26), the graphite heat conducting sheet (25) and the graphite ring (23) are fixedly compressed by the heat reflection cup cover plate (33) and the heat reflection plate connecting upright post (37), so that the left and right shaking is prevented; a heat reflection cup fixing ring (13) is arranged on the half surface of the heat reflection cup (14), one end of the heat reflection cup fixing ring (13) is fixed with the heat reflection cup (14) and a heat reflection cup cover plate (33) through a heat reflection cup connecting upright post (38) and a heat reflection cup base screw hole (16) and a heat reflection cup fixing ring screw hole (17), and the other end of the heat reflection cup fixing ring (13) is fixed with a right-angle connector (8) through a right-angle connector screw hole (12) and a heat reflection cup fixing ring screw hole (17).

Technical Field

The invention relates to the field of physical and application research of plasmas, in particular to a large-size high-emission current density plasma source.

Background

In the existing tokamak feeding mode in the field of magnetic confinement fusion, core feeding is difficult to realize. Through the development of the whole fusion technical field, the compact ring is the only few technologies with core charging potential at present, and the research on the change of the physical parameters of the compact ring injected into the plasma is very important. Therefore, it is necessary to generate high-density background plasma to study the change of plasma parameters after compact ring injection into plasma, and no relevant experimental study is available at present for laying the foundation for future compact ring injection EAST apparatus.

At present, the hot cathode plasma source mainly comprises a thorium tungsten cathode, an oxide cathode and a boride cathode, and the emission current density capability, the anti-poisoning capability, the ion bombardment resistance capability, the evaporation rate capability and the long service life capability of the boride cathode are stronger than those of the thorium tungsten cathode and the oxide cathode. Among boride cathodes, the emissive ability of lanthanum hexaboride materials is most prominent. The plasma source works in vacuum and magnetic field environment, the lanthanum hexaboride cathode material has high working temperature, when the working temperature is reached, a large amount of electrons are generated on the surface of the lanthanum hexaboride cathode material, a bias voltage is applied between the cathode and the anode, and the electrons move under the action of an electric field and collide with neutral gas in a vacuum chamber, so that plasma is generated. Under the magnetic field constraint, the plasma has instability, a current channel is formed between the cathode and the anode, and the current induces a magnetic field, so that the plasma source can be used for researching the basic physical problems of the plasma instability, the magnetic field reconnection, the drift wave turbulence, the ribbon flow and the like.

In a plasma source, the plasma source has many small sizes and low emission current densities, and the achievement of large sizes and high emission current densities faces no small challenge. The small size and low emission current density cannot meet the requirements of background plasmas, and related research cannot be effectively carried out.

Disclosure of Invention

The invention provides a large-size and high-emission current density plasma source, which aims to solve the problems of small size and low emission current density of the existing plasma source, meet the requirements of physical parameters in a compact ring background plasma and research the basic physical problems of plasma instability, magnetic field reconnection, drift wave turbulence, ribbon flow, Alfense wave and the like.

In order to achieve the above object, the invention adopts the technical scheme that:

the utility model provides a plasma source of jumbo size high emission current density, includes positive pole, negative pole, right angle connector, mounting flange, vacuum seal assembly, fluting bar copper, the positive pole includes anode mesh, positive pole solid fixed ring, the positive pole passes through right angle connector and links to each other with the fluting bar copper, the negative pole includes negative pole emitter, negative pole emitter conducting ring, heat source, heat reflection board, heat reflection cup, heat source fixer, heat reflection cup solid fixed ring, insulating material, the negative pole passes through right angle connector and links to each other with the fluting bar copper, fluting bar copper and flange seal through vacuum seal assembly, circulating water cooling and inside function electric current channel are walked to fluting bar copper side, positive pole and negative pole operational environment are vacuum, have a magnetic field. The cathode and the anode are fixed in the vacuum chamber through flanges, and discharge is carried out under the direct current or pulse condition. The anode and the cathode are placed in parallel in the vacuum chamber with a distance of more than one meter. The large-space pulse discharge is realized, a current channel is generated between the anode and the cathode, the working temperature of the cathode is higher, the emission current density is higher, and the density of generated plasma is higher.

According to the large-size high-emission-current-density plasma source, the anode is of a circular net structure and is fixedly compressed through the anode ring, and the penetration rate is 70%.

According to the large-size high-emission current density plasma source, the anode net material is a molybdenum material, and the anode ring material is a stainless steel material.

According to the large-size high-emission current density plasma source, the side surface of the slotted copper rod is provided with a water cooling inlet and a water cooling outlet. The open groove bar copper can have the high current to pass through in the experimentation, has heat production, is used for the cooling.

The positive pole includes positive pole net, positive pole upper fixed ring, positive pole lower fixed ring, and positive pole upper fixed ring, positive pole lower fixed ring one side respectively the recess is used for placing the positive pole net, and it is fixed to draw flat with positive pole net through positive pole upper fixed ring screw.

The vacuum sealing assembly comprises an upper sealing piece, a lower sealing piece, an O-shaped ring, a sealing nut, a copper bar fixing bolt, a sealing flange and an insulating material, wherein the upper sealing piece, the lower sealing piece, the O-shaped ring and the insulating material are all fixed on the sealing flange through the sealing nut and the copper bar fixing bolt, and vacuum air leakage and grooving copper bar damage are prevented.

According to the large-size high-emission current density plasma source, the anode and the cathode work in the vacuum chamber, the anode and the cathode are led out of the vacuum chamber to the outside of the vacuum chamber through the slotted copper rod and the sealing flange, and meanwhile, the heat source electrode is also led out of the vacuum chamber through the slotted copper rod.

The plasma source with large size and high emission current density is characterized in that a groove sealing strip and a groove are subjected to brazing and then polished.

According to the large-size high-emission-current-density plasma source, the cathode emitter material is lanthanum hexaboride, and the size of the cathode emitter material is smaller than 15 cm.

According to the large-size high-emission current density plasma source, the reflection cup is made of molybdenum, and the lanthanum hexaboride is located between the graphite ring and the graphite heat conducting sheet. The cathode emitter is prevented from reacting with refractory metal at high temperature, and the graphite heat conducting sheet has good heat conducting property, so that the cathode emitter is uniformly heated.

The plasma source with large size and high emission current density is provided with a conducting ring around the cathode emitter. The electrical connection of the cathode emitter is ensured, the cathode emitter is protected from being broken due to thermal expansion, and the large size of the cathode emitter can be realized.

According to the large-size high-emission current density plasma source, the high-temperature insulating material is arranged below the graphite heat conducting sheet, and the heat source fixer are arranged below the high-temperature insulating material. The heat source needs a direct current power supply for heating, so a high-temperature insulating material is needed for insulation, the heat conduction performance of the high-temperature insulating material is excellent, and the heat loss is reduced.

According to the large-size high-emission current density plasma source, the heat source is in a snake shape and is made of tungsten materials.

According to the large-size high-emission current density plasma source, heat source screw holes are respectively designed at two ends of a heat source, two ends of the heat source are fixed on a heat source electrode through the heat source screw holes, a circle of the heat source electrode is also provided with a ceramic insulating material to prevent the heat source electrode from contacting with a heat reflection plate, the heat source electrode is fixed on a stainless steel heat source leading-out electrode, the stainless steel heat source leading-out electrode is connected to a slotted copper rod to be led out through a lead, and a heat source fixer is designed to have grooves on two sides and be made of ceramic materials according to the shape of the heat source to play roles in supporting the heat source and insulating.

In order to improve the heat radiation utilization rate, the three layers of heat reflection plates are arranged below the heat source fixer and used for reflecting heat radiated backwards by the heat source so as to enable the heat to return to the cathode emitter. The three layers of heat reflection plate materials are all molybdenum materials, and the molybdenum materials have higher reflectivity at high temperature. The three layers of heat reflection plates are respectively a first heat reflection plate, a second heat reflection plate and a third heat reflection plate. 8 same heat reflection plate connecting upright columns are arranged in the middle of each layer of heat reflection plate, and the material of the heat reflection plate connecting upright columns is molybdenum material.

According to the large-size high-emission-current-density plasma source, heat around a cathode emitter is reflected through a heat reflection cup, meanwhile, a heat reflection cup cover plate is arranged at the bottom of the heat reflection cup, and the heat reflection plate, a heat source fixer, the cathode emitter, a high-temperature insulating material, a graphite heat conducting sheet and a graphite ring are fixedly compressed through the heat reflection cup cover plate and a heat reflection plate connecting upright column, so that the left and right shaking is prevented.

The plasma source with large size and high emission current density is characterized in that a heat reflection cup fixing ring is arranged on the half surface of a heat reflection cup, one end of the heat reflection cup fixing ring is fixed with the heat reflection cup and a heat reflection cup cover plate through a screw hole through a heat reflection cup connecting upright post, and the other end of the heat reflection cup fixing ring is fixed with a right-angle connector through a screw hole.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the cathode emitter of the invention has large size and high emission current density.

(2) The invention has higher current and can realize large-distance discharge.

(3) The invention can be used for researching the basic physical problems of magnetic field reconnection, plasma instability, drift wave turbulence, ribbon flow and the like.

(4) The invention can be used as a compact ring background plasma source to research some physical phenomena of the compact ring injected into the background plasma.

Drawings

FIG. 1 is a schematic diagram of an anode and a cathode of a large-sized plasma source with high emission current density according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the flange vacuum seal assembly of the present invention;

FIG. 3 is a cross-sectional view of an anode of the present invention;

fig. 4 is a cross-sectional view of a cathode of the present invention.

Description of reference numerals:

1-slotted copper bar, 2-water-cooled inlet, 3-lower sealing piece, 4-sealing nut, 5-sealing flange, 6-copper bar fixing bolt, 7-insulating material, 8-right angle connector, 9-anode upper fixing ring, 10-anode upper fixing ring screw hole, 11-anode net, 12-right angle connector screw hole, 13-heat reflection cup fixing ring, 14-heat reflection cup, 15-cathode emitter, 16-heat reflection cup base screw hole, 17-heat reflection cup fixing ring screw hole, 18-slotted sealing strip, 19-water-cooled outlet, 20-upper sealing piece, 21-O-ring, 22-anode lower fixing ring, 23-graphite washer, 24-conducting ring, 25-graphite heat conducting sheet, 26-high temperature insulating material, 27-heat source screw holes, 28-heat source, 29-heat source fixer, 30-first heat reflection plate, 31-second heat reflection plate, 32-third heat reflection plate, 33-heat reflection cup cover plate, 34-ceramic insulating material, 35-heat source electrode, 36-heat source leading-out electrode, 37-heat reflection plate connecting upright post and 38-heat reflection cup connecting upright post.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1-4, a large-sized plasma source with high emission current density comprises an anode, a cathode, a right-angle connector 8, a fixed flange, a vacuum sealing assembly and a slotted copper rod 1, wherein the anode is connected with the slotted copper rod 1 through the right-angle connector 8. The cathode is connected with the slotted copper bar 1 through a right-angle connector 8, the slotted copper bar 1 and the flange are sealed through a vacuum sealing assembly, and the side face of the slotted copper bar 1 is circulated with water cooling and the inside of the slotted copper bar plays a role of a current channel. The working environment of the anode and the cathode is vacuum and has a magnetic field, the cathode and the anode are fixed in the vacuum chamber through flanges, and the anode and the cathode are arranged in the vacuum chamber in parallel and are spaced by more than one meter. The anode and the cathode work in the vacuum chamber, the anode and the cathode are led out of the vacuum chamber through the slotted copper bar 1 and the sealing flange 5, and the heat source electrode 35 is also led out of the vacuum chamber through the slotted copper bar 1.

The side of the slotted copper rod 1 is provided with a water-cooling inlet 2 and a water-cooling outlet 19, and the slotted copper rod 1 can pass high current in the experimental process and generate heat for cooling. The grooved seal 18 and the grooves are polished after brazing.

The vacuum sealing assembly comprises an upper sealing element 20, a lower sealing element 3, an O-shaped ring 21, a sealing nut 4, a copper bar fixing bolt 6, a sealing flange 5 and an insulating material 7, wherein the upper sealing element 20, the lower sealing element 3, the O-shaped ring 21 and the insulating material 7 are all fixed on the sealing flange 5 through the sealing nut 4 and the copper bar fixing bolt 6, and the air leakage of a vacuum chamber and the damage of the slotted copper bar 1 are prevented.

The positive pole includes positive pole net 11, positive pole upper fixed ring 9, positive pole lower fixed ring 22, and positive pole upper fixed ring 9, positive pole lower fixed ring 22 one side respectively the recess is used for placing positive pole net 11, fixes leveling positive pole net 11 through positive pole upper fixed ring screw 10 to prevent to reduce.

The cathode comprises a cathode emitter 15, a cathode emitter conductive ring 24, a heat source 28, a heat reflection plate, a heat reflection cup 14, a heat source holder 29, a heat reflection cup holder ring 13 and an insulating material. The cathode emitter 15 material is lanthanum hexaboride, which is located between the graphite gasket 23 and the graphite heat conducting sheet 25. The cathode emitter 15 is prevented from reacting with refractory metals at high temperature, the graphite heat conducting fins 25 have good heat conducting performance, so that the cathode emitter 15 is uniformly heated, the conducting rings 24 are arranged around the cathode emitter 15, the electrical connection of the cathode emitter 15 is ensured, the cathode emitter 15 is protected from being broken due to thermal expansion, and the cathode emitter 15 can be made to be large-sized.

In order to reduce the heat loss, insulate the heat source 28 from the cathode emitter 15, and heat the cathode emitter 15 uniformly, a boron nitride insulating material 26 is provided under the graphite heat-conducting sheet 25, a heat source 28 and a heat source holder 29 are provided under the high-temperature insulating material 26, and the heat source holder 29 is also made of a boron nitride material. The heat source 28 requires a dc power source for heating, and therefore requires the high-temperature insulating material 26 for insulation, and the high-temperature insulating material 26 has excellent heat conductivity, thereby reducing heat loss. The heat source 28 is in a snake shape, heat source screw holes 27 are respectively designed at two ends of the heat source 28, the two ends of the heat source 28 are fixed on a heat source electrode 35 through the heat source screw holes 27, a ceramic insulating material 34 is also arranged in one circle of the heat source electrode 35 to prevent the heat source electrode 35 from contacting with a heat reflection plate, the heat source electrode 35 is fixed on a stainless steel heat source leading-out electrode 36, the stainless steel heat source leading-out electrode 36 is connected on the slotted copper rod 1 to be led out through a lead, and the heat source fixer 29 is designed to have grooves on two sides and be made of ceramic materials according to the shape of the heat source to play roles of supporting the heat source 28 and insulating.

In order to improve the heat radiation utilization, three layers of heat reflecting plates, namely a first heat reflecting plate 30, a second heat reflecting plate 31 and a third heat reflecting plate 32, are arranged below the heat source holder 29 to reflect the heat radiated backward from the heat source 28 and return the heat to the cathode emitter 15, and 8 identical heat reflecting plate connecting pillars 37 are arranged in the middle of each layer of heat reflecting plate.

The heat around the cathode emitter 15 is reflected by the heat reflection cup 14, meanwhile, a heat reflection cup cover plate 33 is arranged at the bottom of the heat reflection cup 14, and the heat reflection plate, the heat source 28, the heat source fixer 29, the cathode emitter 15, the high-temperature insulating material 26, the graphite heat conducting sheet 25 and the graphite ring 23 are fixedly pressed tightly through the heat reflection cup cover plate 33 and the heat reflection plate connecting upright post 37, so that the left and right shaking is prevented. A heat reflection cup fixing ring 13 is arranged on the half surface of the heat reflection cup 14, one end of the heat reflection cup fixing ring 13 is fixed with the heat reflection cup 14 and the heat reflection cup cover plate 33 through a heat reflection cup connecting upright post 38 and a heat reflection cup base screw hole 16 and a heat reflection cup fixing ring screw hole 17, and the other end of the heat reflection cup fixing ring 13 is fixed with the right-angle connector 8 through a right-angle connector screw hole 12 and a heat reflection cup fixing ring screw hole 17.

The working principle of the embodiment of the invention is as follows:

a plasma source with large size and high emission current density is in vacuum and has magnetic field. The cathode and the anode are fixed in a vacuum chamber (not shown) through flanges, two handle coils (not shown) are arranged at symmetrical positions on the inner sides of the cathode and anode flanges, the anode and the cathode are arranged in the vacuum chamber in parallel at a distance of more than one meter, and large-space pulse discharge is realized. The lanthanum hexaboride cathode material has high working temperature, when the working temperature is reached, a large number of electrons are generated on the surface of the lanthanum hexaboride cathode material, pulse bias voltage is applied between the cathode and the anode, and the electrons move under the action of an electric field and collide with neutral gas in a vacuum chamber (not shown), so that plasma is generated. Under the magnetic field constraint, plasma has instability, a current channel is formed between a cathode and an anode, current can induce a magnetic field, the working temperature of the cathode is high, the emission current density is high, the density of the generated plasma is high, the method can be used for researching basic physical problems of magnetic field reconnection, plasma instability, drift wave turbulence, ribbon flow and the like, and can also be used as a compact ring background plasma source to lay a foundation for injecting an EAST device into a compact ring later.

It should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the structure of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.