CN220475974U - Electrostatic probe and electrostatic probe - Google Patents
Electrostatic probe and electrostatic probe Download PDFInfo
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- CN220475974U CN220475974U CN202322124696.6U CN202322124696U CN220475974U CN 220475974 U CN220475974 U CN 220475974U CN 202322124696 U CN202322124696 U CN 202322124696U CN 220475974 U CN220475974 U CN 220475974U
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- electrode
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- electrostatic probe
- plasma
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- 239000000523 sample Substances 0.000 title claims abstract description 96
- 230000003068 static effect Effects 0.000 claims abstract description 10
- 238000005339 levitation Methods 0.000 claims abstract description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 239000010937 tungsten Substances 0.000 claims description 4
- 229910002601 GaN Inorganic materials 0.000 claims description 3
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 7
- 210000002381 plasma Anatomy 0.000 description 37
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- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 239000010963 304 stainless steel Substances 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 1
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- 238000003745 diagnosis Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
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- Plasma Technology (AREA)
Abstract
The utility model discloses an electrostatic probe and an electrostatic probe, the electrostatic probe comprises: a first electrode (6) for measuring a levitation potential at a first location; a second electrode (7); a third electrode (8) and a second electrode (7) form a group of double probes; a fourth electrode (9) for measuring a floating potential at the second location, the first electrode (6) and the fourth electrode (9) together measuring electrostatic information of the plasma; the electrostatic probe further comprises a probe main body, wherein the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged on the probe main body, and the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged and designed into square shapes with equal intervals. The static probe is simple in structure and accurate in measurement result.
Description
Technical Field
The utility model relates to the technical field of plasma diagnosis, in particular to an electrostatic probe and an electrostatic probe.
Background
Controllable nuclear fusion refers to a technology for fusion of hydrogen element and release of energy for power generation and other purposes. Unlike fission-based nuclear energy technologies that are currently commercially available, the reaction products of controlled nuclear fusion are relatively environmentally friendly and do not produce significant amounts of radioactive waste. However, it is not easy to achieve controlled nuclear fusion, and scientists have been struggling to find a viable approach due to the stringent requirements of the reaction conditions, where nuclear fusion studies based on tokamak devices have been leading. In recent 20 years, a low ring to diameter tokamak device, also known as a spherical tokamak, has been developed rapidly. Compared with the conventional tokamak device, the low-ring-diameter-ratio tokamak device has the advantages of small ring diameter ratio, thinner center column, simple structure and low cost, and the generated plasma has the characteristics of the conventional tokamak, as well as strong ring effect, large deformation, high elongation ratio, high beta, high current and the like.
The Nanchang spherical Tokamak (NCST), built in 2020 and successfully discharged, was a low ring to diameter Tokamak device aimed at exploring a method of plasma initiated fusion compression. The large radius r=0.4m, the small radius a=0.24 m, the toroidal magnetic field (TF) bt=0.36T, and the plasma current (Ip) can reach 100kA.
The electrostatic probe, also called Langmuir probe, is a solid probe widely used in low temperature plasmas and in boundary areas or divertors of high temperature plasmas. The theoretical basis of the electrostatic probe is the plasma sheath theory. In particular, for tokamak devices, electrostatic probes are one of the most commonly used diagnostic tools for measuring parameters such as plasma density, temperature, velocity and potential. Because of the instability of the plasma motion, real-time monitoring and control with an electrostatic probe is required. Electrostatic probes are typically implemented by selecting a small metal sphere or cylinder, the diameter of which is typically varied from a few millimeters to a few centimeters. The probe is placed near the plasma and the potential of the probe surface will be affected by the plasma potential. When the plasma moves or changes, the potential of the probe surface will also change. By measuring the potential change of the ball surface, the relevant parameters of the plasma can be obtained.
The electrostatic probe on the tokamak device, as a commonly used diagnostic tool, has the following roles and meanings:
1. measuring plasma parameters: parameters such as plasma density, temperature, velocity and potential are very important information for plasma research and control. The electrostatic probe can measure these parameters by utilizing the changes of plasma potential and charge, and provides important parameters for the study of plasma physics.
2. Monitoring the stability of the plasma: the plasma motion has instability, and vortex, oscillation, irregular motion and other phenomena often occur. The static probe can monitor the movement of the plasma in real time so as to ensure the stability of the plasma.
3. Auxiliary device control: the static probe can reflect the state change of the plasma, and the control and adjustment of the plasma can be realized by controlling parameters such as plasma discharge, heating, boundary conditions and the like.
In the process of realizing the technical scheme of the embodiment of the application, the inventor at least finds that the following technical problems exist in the prior art:
the electrostatic probe is typically composed of a plurality of electrodes, which are placed around the plasma. The main structure is as follows: 1. an electrode: the exposed lead is connected with an electrified instrument at the rear end; 2. a shell: an insulator material wrapped around the wire for supporting the conductor. The working principle of the electrostatic probe is based on the charge collection effect. When the electrode of the electrostatic probe enters the plasma, ions and electrons in the plasma are adsorbed to the electrode surface, and the potential of the electrode is changed accordingly. By this change, electrostatic parameter information of the plasma can be obtained.
The existing electrostatic probes currently have a multi-step probe and three-probe structure. The multi-step probe can measure plasma parameters at multiple point locations as shown in fig. 1, but is more complex in structure. The three probes have a single electrode for measuring the suspension potential, and the measurement result has a certain error.
In conclusion, the existing electrostatic probe has the technical problems of complex structure and inaccurate measurement.
Disclosure of Invention
The embodiment of the application provides an electrostatic probe and an electrostatic probe, which solve the technical problems of complex structure and inaccurate measurement of the existing electrostatic probe.
An embodiment of the present application provides an electrostatic probe, the electrostatic probe includes: a first electrode (6) for measuring a levitation potential at a first location; a second electrode (7); a third electrode (8) forming a set of double probes with the second electrode (7); a fourth electrode (9) for measuring a levitation potential at a second location, the first electrode (6) and the fourth electrode (9) together measuring electrostatic information of the plasma; the static probe further comprises a probe main body, wherein the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged on the probe main body, and the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged and designed into squares with equal intervals.
Optionally, the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are in particular tungsten electrodes.
The embodiment of the application also provides an electrostatic probe, which comprises: the electrostatic probe of the foregoing embodiment; the CF250 flange is provided with the electrostatic probe; the KF150 flange is connected with the CF250 flange through screws; the guide rail is connected with the KF150 flange through screws; and the stepping motor is connected with the guide rail through a screw.
Optionally, the electrostatic probe further comprises: a connector; the support rod is arranged on the CF250 flange and is connected with the electrostatic probe through a screw; the guide rod is arranged on the KF150 flange and is connected with the support rod through the connector.
One or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:
the arrangement of the electrodes of the electrostatic probe is designed into squares with equal spacing, and the structure is simple. The first electrode and the fourth electrode of the static probe can measure the suspension potential at different positions, so that the measurement error can be reduced to a certain extent, and the measurement result is accurate.
The existing electrostatic probe is not suitable for high-temperature plasma due to the limitation of materials, and the electrode and the supporting structure of the existing electrostatic probe can generate thermal expansion problem under the high-temperature plasma environment, and even can cause melting of the electrode. For example, graphite probes begin to soften in a vacuum environment at about 3000 ℃, while the electrodes of the electrostatic probes of the present application employ tungsten electrodes with melting points up to 3400 ℃ and the probe body employs gallium nitride bodies with melting points at 1500 ℃. The temperature resistance of the electrostatic probe is greatly improved.
The static probe of this application has reserved KF150 flange window, can be according to follow-up experiment requirement can conveniently change static probe through the connector for this design is more nimble.
Drawings
FIG. 1 is a schematic diagram of a prior art stepped probe;
FIG. 2 is a schematic structural diagram of an electrostatic probe according to an embodiment of the present application;
FIG. 3 is a cross-sectional view of an electrostatic probe in an embodiment of the present application;
FIG. 4 is a schematic structural diagram of an electrostatic probe according to an embodiment of the present application;
fig. 5 is a circuit diagram of an electrostatic probe in an embodiment of the present application.
Detailed Description
The embodiment of the application provides an electrostatic probe and an electrostatic probe, which solve the technical problems of complex structure and inaccurate measurement of the existing electrostatic probe.
The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model.
As shown in fig. 2, 1 is an electrostatic probe; part 2 is a CF250 flange; component 3 is a KF150 flange for viewing the interior and facilitating replacement of the head; the component 4 is a guide rail with a travel of 20cm; the member 5 is a stepper motor for driving the movement of the electrostatic probe. The processing material of the static probe except the static probe electrode adopts 304 stainless steel material, the processing material of the electrode is tungsten, and the probe body is gallium nitride material (used for insulation between the electrode and the supporting material thereof).
As shown in fig. 3, the CF250 flange 2, KF150 flange 3, guide rail 4 and stepper motor 5 are connected by screws, and the electrostatic probe 1 has M2 screws at four corners connected to the support bar. The component 10 is a connector, the supporting rod is connected with the guide rod by the connector, and the connector is used for conveniently disassembling the electrostatic probe.
As shown in fig. 4 (c), 6, 7, 8 and 9 are four electrodes of the electrostatic probe. Wherein the first electrode 6 and the fourth electrode 9 are used for measuring the levitation potential at different positions; the second electrode 7 and the third electrode 8 form a group of double probes, and the double probes and the first electrode 6 and the fourth electrode 9 measure electrostatic information of plasma together, including parameter information such as plasma potential, electron density, electron temperature and the like. The four electrodes were, as shown in FIGS. 4 (a) and 4 (b), cylindrical in shape, and had a circular bottom surface with a diameter of 1mm, and the exposed portion contacting the plasma was 2mm long.
As shown in fig. 5, wherein the plasma region is schematically shown within the dashed box, R1, R2 and R3 are resistors, and the power supply is for applying a sufficiently large voltage to the second electrode 7 and the third electrode 8. The open circles are used for connecting a later-stage collector, so that data storage and subsequent data processing are facilitated.
The data processing process comprises the following steps:
first, the power supply is applied to a voltage large enough that the current flowing through the second electrode 7 and the third electrode 8 is a saturated ion current. The voltages of the four electrodes are:
electron density:
wherein kappa is B Is the boltzmann constant.
Electron temperature:
wherein I is D I for the magnitude of the current flowing through the electrodes 7 and 8 D ＝(V 1 -V 2 ) 2; alpha is generally 0.61; c (C) s Is the ion sound velocity, C s ＝(κ B T e /m i ) 1/2 ；A p A for the collection area of the probe p ＝7.07mm 2 。
It will be apparent to those skilled in the art that various modifications and variations can be made to the present utility model without departing from the spirit or scope of the utility model. Thus, it is intended that the present utility model also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (5)
1. An electrostatic probe, the electrostatic probe comprising:
a first electrode (6) for measuring a levitation potential at a first location;
a second electrode (7);
a third electrode (8) forming a set of double probes with the second electrode (7);
a fourth electrode (9) for measuring a levitation potential at a second location, the first electrode (6) and the fourth electrode (9) together measuring electrostatic information of the plasma;
the static probe further comprises a probe main body, wherein the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged on the probe main body, and the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are arranged and designed into squares with equal intervals.
2. The electrostatic probe according to claim 1, characterized in that the first electrode (6), the second electrode (7), the third electrode (8) and the fourth electrode (9) are in particular tungsten electrodes.
3. An electrostatic probe according to claim 1, wherein the probe body is in particular a gallium nitride body.
4. An electrostatic probe, the electrostatic probe comprising:
an electrostatic probe as claimed in any one of claims 1 to 3;
the CF250 flange is provided with the electrostatic probe;
the KF150 flange is connected with the CF250 flange through screws;
the guide rail is connected with the KF150 flange through screws;
and the stepping motor is connected with the guide rail through a screw.
5. The electrostatic probe of claim 4, wherein the electrostatic probe further comprises:
a connector;
the support rod is arranged on the CF250 flange and is connected with the electrostatic probe through a screw;
the guide rod is arranged on the KF150 flange and is connected with the support rod through the connector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322124696.6U CN220475974U (en) | 2023-08-08 | 2023-08-08 | Electrostatic probe and electrostatic probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322124696.6U CN220475974U (en) | 2023-08-08 | 2023-08-08 | Electrostatic probe and electrostatic probe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220475974U true CN220475974U (en) | 2024-02-09 |
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ID=89799216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322124696.6U Active CN220475974U (en) | 2023-08-08 | 2023-08-08 | Electrostatic probe and electrostatic probe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220475974U (en) |
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2023
- 2023-08-08 CN CN202322124696.6U patent/CN220475974U/en active Active
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