A real-time monitoring activity limiter for quasi-circular symmetric phasar

Abstract

The application provides a real-time monitoring activity limiter for quasi-cyclic symmetric stellarator, which comprises a limiter head and a temperature correction unit; the limiter head is arranged inside a vacuum chamber of the quasi-cyclic symmetric stellarator; a probe array, an armored thermocouple and a graphite protective layer facing the plasma in the vacuum chamber are arranged on the limiter head; the graphite protective layer covers the probe array, and the probes in the probe array penetrate the surface of the graphite protective layer; the armored thermocouple is embedded in the graphite protective layer and used for collecting the temperature signal of the limiter head in real time; and the temperature correction unit is connected with the armored thermocouple. By integrating the probe array and the armored thermocouple on the limiter head and covering the probe array with the graphite protective layer while making the probe tips penetrate and expose, the synchronous monitoring of the plasma boundary parameters and the temperature of the limiter body is realized.

Description

Technical Field

[0001] This invention relates to the field of magnetic confinement nuclear fusion technology, and more specifically, to a real-time monitoring activity limiter for a quasi-toroidal stellarator. Background Technology

[0002] The content in this section only provides background information related to this invention and may not constitute prior art.

[0003] In the field of magnetic confinement nuclear fusion research, stellarators have become an important platform for conducting plasma physics experiments due to their inherent steady-state operation capabilities. Among them, quasi-toroidal stellarators, through optimization of the magnetic field configuration, significantly improve particle confinement performance while retaining the advantages of steady-state operation. However, the high-precision magnetic field configurations employed by these devices place higher demands on the boundary control and experimental diagnostic capabilities of the plasma.

[0004] As a key component directly facing the plasma, the limiter is located between the plasma boundary and the inner wall of the vacuum chamber. Its main functions are to withstand the plasma thermal load, protect the inner wall of the vacuum chamber, and assist in the formation of the plasma boundary. With the deepening of experimental research on quasi-toroidal stellarators, more refined requirements have been placed on the performance of the limiter.

[0005] In terms of monitoring, to evaluate particle confinement performance, study transport processes, and prevent overheating damage, it is necessary to measure plasma boundary parameters (such as electron temperature and ion saturation flux) and the temperature of the portion of the confinement unit located inside the vacuum chamber in real time. Among these, accurate monitoring of the temperature of the confinement unit inside the vacuum chamber is particularly important. If the temperature of this portion of the confinement unit becomes too high during operation, it may lead to material melting, evaporation, or even a plasma rupture accident. Therefore, real-time and accurate monitoring of the temperature of the confinement unit inside the vacuum chamber is a crucial prerequisite for ensuring the safe operation of the device and conducting physical analysis. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a real-time monitoring activity limiter for a quasi-toroidal stellarator, which is intended to be able to monitor the temperature of the portion of the limiter located inside the vacuum chamber in real time and accurately.

[0007] The objective of this invention is achieved through the following technical solution: This invention provides a real-time monitoring activity limiter for a quasi-annular symmetric stellarator, including a limiter head and a temperature correction unit; The limiter head is located inside the vacuum chamber of the quasi-annular stellarator; the limiter head is provided with a probe array, a sheathed thermocouple, and a graphite protective layer facing the plasma inside the vacuum chamber. The graphite protective layer covers the probe array, and the probes in the probe array penetrate the surface of the graphite protective layer; the probe array is used to detect plasma boundary parameters inside the vacuum chamber. The armored thermocouple is embedded inside the graphite protective layer and is used to collect the temperature signal of the limiter head in real time. The temperature correction unit is connected to the armored thermocouple signal; the temperature correction unit is configured to: acquire the radiation intensity signal of the graphite protective layer surface collected by the external infrared temperature measuring device, calculate the emissivity of the graphite protective layer surface based on the Stefan-Boltzmann law according to the temperature signal and the radiation intensity signal, and use the calculated emissivity to correct the two-dimensional temperature distribution collected by the external infrared temperature measuring device, so as to output the corrected temperature distribution data.

[0008] Optionally, there are multiple armored thermocouples, which are respectively embedded in different positions of the graphite protective layer.

[0009] Optionally, the real-time monitoring activity limiter for the quasi-circular symmetric stellarator further includes a drive mechanism; the drive mechanism includes a push rod and a push assembly; the first end of the push rod is connected to the head of the limiter; the push assembly is used to drive the push rod to perform reciprocating linear motion in a predetermined direction; An angle adjustment structure is provided at the connection between the push rod and the limiter head; the angle adjustment structure is used to adjust the polar angle of the limiter head relative to the push rod.

[0010] Optionally, the angle adjustment structure includes an arc-shaped channel and a locking bolt disposed at the first end of the push rod; The limiter head is rotatably connected to the first end of the push rod by a fixing bolt, and the locking bolt passes through the limiter head and the arc-shaped channel to lock the limiter head to the first end of the push rod; When the locking bolt is loosened, the limiter head can rotate along the arc-shaped channel to adjust the polar angle of the limiter head relative to the push rod.

[0011] Optionally, a ceramic insulating sheet is provided at the connection between the first end of the push rod and the head of the limiter, and a ceramic insulating sleeve is fitted on the screw of both the fixing bolt and the locking bolt.

[0012] Optionally, the drive mechanism may further include a bellows, a loose flange, and a transition flange; The adapter flange is fixedly connected to the outer wall of the vacuum chamber; One end of the bellows is sealed and fixedly connected to the transition flange, and the other end of the bellows is sealed and fixedly connected to the loose flange. The second end of the push rod passes through the adapter flange, the bellows, and the loose flange in sequence, and the push rod and the loose flange are sealed and fixedly connected. The propulsion assembly is located outside the vacuum chamber. The output end of the propulsion assembly is fixedly connected to the slip-on flange and is used to drive the slip-on flange to reciprocate linearly in a predetermined direction, thereby driving the propulsion rod to move synchronously.

[0013] Optionally, the limiter head is further provided with a lead wire channel, and the second end of the push rod is provided with a signal output port; The lead channel passes through the interior of the push rod and is connected to the signal lead-out port, allowing the signal lines connecting the probe array and the armored thermocouple to pass through.

[0014] Optionally, the limiter head includes a support plate and a mounting bracket; One end of the support plate is connected to the first end of the push rod; The mounting bracket is fixedly disposed on one side of the support plate and is U-shaped; the probe array is mounted on the mounting bracket; The graphite protective layer is fixedly connected to the support plate and covers the probe array and the mounting bracket; The support plate is provided with a square tube, and the internal channel of the square tube is connected to the U-shaped groove of the mounting bracket and the internal channel of the push rod; the U-shaped groove of the mounting bracket, the internal channel of the square tube, and the internal channel of the push rod together constitute the lead wire channel.

[0015] Optionally, the probe array includes multiple probe groups, each probe group including a probe, a brass pillar, and a ceramic sleeve; The brass post is embedded inside the ceramic sleeve, and the rear end of the probe is connected to the brass post; The mounting bracket is provided with mounting holes corresponding to the plurality of probe groups, and the mounting holes are connected to the U-shaped grooves of the mounting bracket; the ceramic sleeves of each probe group are embedded in the corresponding mounting holes; The graphite protective layer is provided with stepped holes corresponding to the plurality of probe groups. The stepped holes include a small diameter end and a large diameter end. The small diameter end penetrates the surface of the graphite protective layer, and the large diameter end mates with the ceramic sleeve. The ceramic sleeves of each probe group are simultaneously embedded in the large-diameter end of the corresponding mounting hole and the corresponding stepped hole, and the detection end of the probe of each probe group is located in the small-diameter end of the corresponding stepped hole, so that the probe is exposed to the surface of the graphite protective layer.

[0016] Optionally, the graphite protective layer is formed by joining a first protective layer and a second protective layer together; the joint between the first protective layer and the second protective layer adopts a stepped overlapping structure. The graphite protective layer is fixedly connected to the head of the limiter by connecting bolts. The graphite protective layer is provided with a connecting hole for accommodating the nut of the connecting bolts. A graphite plug for covering the nut of the connecting bolts is provided in the connecting hole.

[0017] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: 1. This invention achieves synchronous monitoring of plasma boundary parameters and the temperature of the limiter body by integrating a probe array and a sheathed thermocouple at the head of the limiter, and covering the probe array with a graphite protective layer while exposing the probe tips. The temperature correction unit, based on the real temperature signal collected by the sheathed thermocouple and the radiation intensity signal collected by the external infrared thermometer, uses the Stefan-Boltzmann law to inversely calculate the emissivity of the graphite protective layer surface in real time. This emissivity is then used to perform pixel-by-pixel correction on the two-dimensional temperature distribution collected by the infrared thermometer, effectively overcoming the influence of dynamic changes in emissivity on the accuracy of infrared thermometry. This ensures both the accuracy of temperature measurement and the acquisition of a complete two-dimensional temperature distribution.

[0018] 2. By further adding a driving mechanism, an angle adjustment structure, and a related vacuum sealing structure, this invention can achieve linear displacement adjustment of the limiter head in the vacuum chamber without damaging the vacuum environment, and can also achieve flexible adjustment of the limiter head's polar angle, so that the limiter head can more accurately match the complex three-dimensional magnetic surface structure formed in the vacuum chamber of the quasi-toroidal stellarator. Attached Figure Description

[0019] Figure 1 A schematic diagram of the structure of a real-time monitoring activity limiter for a quasi-circular symmetric stellarator provided for an embodiment of the present invention; Figure 2 for Figure 1 The diagram shows a structural schematic of the restrictor head from another perspective. Figure 3 for Figure 2 The exploded view of the restrictor head structure shown in the image; Figure 4 for Figure 2 The top view of the restrictor head shown in the image; Figure 5 for Figure 4 Sectional view along the middle AA direction; Figure 6 for Figure 4 Sectional view along the BB direction; Figure 7 for Figure 5 Enlarged view of the local structure at point C; Figure 8 for Figure 4 Sectional view along the DD direction; Figure 9 for Figure 1 The schematic diagram of the drive mechanism shown in the figure; Figure 10 for Figure 1 Enlarged view of the local structure at point E; Figure 11 for Figure 9 Enlarged view of the local structure at point F.

[0020] Icons: 100-Limiter head, 101-Support plate, 102-Mounting bracket, 103-Mounting hole, 104-U-groove, 105-Square tube, 10-Probe array, 11-Probe group, 111-Probe, 112-Brass pillar, 113-Ceramic sleeve, 20-Sheathed thermocouple, 30-Graphite protective layer, 31-First protective layer, 32-Second protective layer, 33-Stepped hole, 331-Small diameter end, 332-Large diameter end, 34-Connecting bolt, 35-Connector Hole, 36-Graphite plug, 40-Drive mechanism, 41-Push rod, 42-Push assembly, 421-Screw rod, 422-Moving end plate, 423-Fixed end plate, 424-Guide column, 425-Handwheel, 43-Bellwall, 44-Loose flange, 45-Adapter flange, 46-Indicator plate, 50-Angle adjustment structure, 51-Arc-shaped channel, 52-Locking bolt, 53-Fixing bolt, 60-Ceramic insulating sheet, 70-Ceramic insulating sleeve, 80-Signal output port. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. The same reference numerals in the accompanying drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the described embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] Compared to the embodiments shown in the accompanying drawings, feasible embodiments within the scope of protection of this invention may have fewer components, other components not shown in the drawings, different components, components with different arrangements, or components with different connections, etc. Furthermore, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0023] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Example 1

[0024] Please refer to Figures 1 to 8 As shown, Embodiment 1 of the present invention provides a real-time monitoring activity limiter for a quasi-annular stellarator. The limiter includes a limiter head 100 and a temperature correction unit (not shown in the figure).

[0025] The limiter head 100 is located inside the vacuum chamber of the quasi-toroidal stellarator. Specifically, the limiter head 100 is the core component facing the plasma inside the vacuum chamber. The limiter head 100 is equipped with a probe array 10, a sheathed thermocouple 20, and a graphite protective layer 30 facing the plasma inside the vacuum chamber. As a material directly facing the plasma, the graphite protective layer 30 has good thermal shock resistance and thermal load resistance, and can withstand the high heat flux density generated by plasma bombardment, while protecting the internal structure of the limiter head 100 from damage.

[0026] A graphite protective layer 30 covers the probe array 10. In an embodiment of the invention, the probe array 10 is a Langmuir probe array, with probes 111 penetrating the surface of the graphite protective layer 30 to detect plasma boundary parameters inside the vacuum chamber. Figure 2 Specifically, the graphite protective layer 30 completely covers the main body of the probe array 10, forming effective thermal and physical protection. The detection end of each probe 111 in the probe array 10 penetrates the surface of the graphite protective layer 30, exposing the detection end of each probe 111 and allowing it to directly contact the plasma boundary region. By applying different bias voltages to the probes 111 and measuring the corresponding current signals, key plasma boundary parameters such as electron temperature, electron density, levitation potential, and ion saturation current can be obtained. This structural design, combining coverage and penetration, ensures both the mechanical stability of the probe array 10 under high temperature and strong magnetic field conditions and the accurate acquisition of plasma boundary parameters by the probes 111.

[0027] Reference Figure 3 or Figure 6As shown, the sheathed thermocouple 20 is embedded inside the graphite protective layer 30 to collect the temperature signal of the limiter head 100 in real time. The sheathed thermocouple 20 has advantages such as fast response, high accuracy, and strong anti-interference capability. Its hot junction is embedded inside the graphite protective layer 30, enabling it to sense the temperature change of the graphite protective layer 30 in real time based on the Seebeck effect. During the operation of the quasi-toroidal stellarator, the interaction between the plasma and the limiter head 100 generates a large amount of heat load, causing the surface temperature of the graphite protective layer 30 to rise. The temperature signal collected by the sheathed thermocouple 20 reflects the actual thermal state of the limiter head 100 and is an important basis for judging whether the limiter head 100 is overheated and assessing the heat load distribution.

[0028] The temperature correction unit is connected to the sheathed thermocouple 20 via a signal line. The temperature correction unit can be located outside the vacuum chamber and connected to the sheathed thermocouple 20 to receive the temperature signal acquired in real time by the sheathed thermocouple 20. For example, the temperature correction unit can be the control system of the quasi-toroidal stellarator itself.

[0029] The temperature correction unit is configured to: acquire the radiation intensity signal of the graphite protective layer 30 surface collected by the external infrared temperature measuring device; calculate the emissivity of the graphite protective layer 30 surface based on the Stefan-Boltzmann law according to the temperature signal collected by the armored thermocouple 20 and the radiation intensity signal collected by the infrared temperature measuring device; and use the calculated emissivity to correct the two-dimensional temperature distribution collected by the external infrared temperature measuring device, so as to output the corrected temperature distribution data.

[0030] Specifically, the infrared thermometer, as an external measuring device, can non-contactly acquire two-dimensional radiation intensity images of the graphite protective layer 30 surface. For example, the infrared thermometer can be an infrared camera positioned outside the vacuum chamber, acquiring the corresponding image through a transparent vacuum window. Although the two-dimensional radiation intensity images acquired by the infrared thermometer have the advantages of high spatial resolution and fast response speed, the accuracy of infrared thermometry is highly dependent on the accuracy of the emissivity of the measured surface. During the operation of the quasi-toroidal stellarator, the surface morphology and roughness of the graphite protective layer 30 change after being bombarded by plasma, causing dynamic drift in emissivity. If a fixed emissivity is used for temperature inversion, significant errors can easily be introduced.

[0031] Therefore, embodiments of the present invention combine the armored thermocouple 20 with an infrared temperature measuring device, using the reference temperature measured by the armored thermocouple 20 to perform real-time correction of the infrared temperature measurement results. Specifically, the temperature correction unit first receives the actual temperature signal of a certain point on the graphite protective layer 30 collected by the armored thermocouple 20, and simultaneously acquires the radiation intensity signal corresponding to that point collected by the infrared temperature measuring device. According to the Stefan-Boltzmann law, radiation intensity is proportional to the fourth power of temperature, i.e. Where P is the radiation intensity, ε is the emissivity, σ is the Stefan-Boltzmann constant, and T is the temperature. Given the temperature T and radiation intensity P, the actual emissivity ε of the graphite protective layer 30 surface under the current condition can be calculated. 实 .

[0032] The actual emissivity ε of the surface of the graphite protective layer 30 was obtained. 实 Then, the temperature correction unit can use this actual emissivity to perform pixel-by-pixel correction on the full-frame two-dimensional radiation intensity image acquired by the infrared thermometer. Specifically, for each pixel in the full-frame two-dimensional radiation intensity image, based on its radiation intensity P... ij and the determined emissivity ε 实 Through formula The actual temperature corresponding to that pixel can then be calculated; where P ij T represents the radiation intensity corresponding to the pixel in the i-th row and j-th column of the full-frame two-dimensional radiation intensity image; ij This represents the temperature value corresponding to the pixel in the i-th row and j-th column of the full-frame two-dimensional radiation intensity image. Based on this, by obtaining the actual temperature corresponding to all pixels in the full-frame two-dimensional radiation intensity image, the two-dimensional temperature distribution data of the entire graphite protective layer 30 surface can be output.

[0033] Through the above methods, embodiments of the present invention achieve accurate online monitoring of the temperature of the confinement head 100. On the one hand, the armored thermocouple 20 provides a high-precision temperature reference; on the other hand, the infrared temperature measurement device provides high spatial resolution two-dimensional temperature field information. Through real-time correction by the temperature correction unit, the influence of dynamic changes in emissivity on the accuracy of infrared temperature measurement is effectively overcome, ensuring both the accuracy of temperature measurement and obtaining a complete two-dimensional temperature distribution. Simultaneously, the synergistic integration of the probe array 10 and the temperature monitoring function enables the confinement device to monitor its own thermal state in real time while monitoring plasma boundary parameters, providing reliable support for evaluating particle confinement performance, studying transport processes, and preventing overheating damage, effectively improving the reliability of the confinement device.

[0034] In a preferred embodiment of the present invention, to further improve the accuracy of temperature measurement and calibration precision, multiple sheathed thermocouples 20 are provided and embedded in different positions of the graphite protective layer 30. By arranging multiple sheathed thermocouples 20 in different positions, multiple reference temperatures can be provided, offering more and more reliable data support for the calibration of infrared temperature measurement.

[0035] In a preferred embodiment of the present invention, in order to achieve precise fixation and electrical isolation of the probe array 10, the embodiments of the present invention employ a multi-positioning and insulation structure.

[0036] Specifically, refer to Figure 3 and Figure 7 As shown, the probe array 10 includes multiple probe groups 11. Each probe group 11 includes a probe 111, a brass pillar 112, and a ceramic sleeve 113. The brass pillar 112 is embedded inside the ceramic sleeve 113, and the rear end of the probe 111 (i.e., the end opposite to its detection end) is connected to the brass pillar 112. The brass pillar 112 serves as a conductive connector, used to transmit the signal collected by the probe 111 to an external control system; the ceramic sleeve 113 provides electrical isolation, ensuring insulation between the probe 111 and the limiter head 100. In this embodiment of the invention, the probe 111 can be a tungsten electrode probe with a diameter of 3 mm, and the ceramic sleeve 113 is made of alumina.

[0037] Reference Figure 3 and Figure 5 As shown, the limiter head 100 includes a support plate 101 and a mounting bracket 102. The support plate 101 may be a 10mm thick 316L stainless steel plate. The mounting bracket 102 is fixedly disposed on one side of the middle of the support plate 101 and is U-shaped. The probe array 10 is mounted on the mounting bracket 102. A graphite protective layer 30 is fixedly connected to the support plate 101 and covers the probe array 10 and the mounting bracket 102 to ensure that the probe array 10 is completely covered.

[0038] Specifically, the mounting bracket 102 is provided with mounting holes 103 corresponding to the multiple probe groups 11 one by one. The ceramic sleeve 113 of each probe group 11 is embedded in the corresponding mounting hole 103 to achieve the initial positioning of the probe group 11 on the mounting bracket 102. For example, the mounting hole 103 can be a through hole with a diameter of 4mm to fit the rear end of the ceramic sleeve 113, so that the ceramic sleeve 113 can be reliably embedded in the mounting hole 103.

[0039] Meanwhile, the graphite protective layer 30 is provided with stepped holes 33 corresponding to the multiple probe groups 11. (See reference...) Figure 7 As shown, the stepped hole 33 includes a small-diameter end 331 and a large-diameter end 332. The small-diameter end 331 penetrates the surface of the graphite protective layer 30, and the large-diameter end 332 mates with the ceramic sleeve 113. The ceramic sleeve 113 of each probe group 11 is simultaneously embedded in the corresponding mounting hole 103 and the large-diameter end 332 of the corresponding stepped hole 33, forming a double clamping structure of the mounting bracket 102 and the graphite protective layer 30 on the ceramic sleeve 113. The detection end of the probe 111 of each probe group 11 is located in the small-diameter end 331 of the corresponding stepped hole 33, so that the detection end of the probe 111 is exposed to the surface of the graphite protective layer 30, thereby collecting plasma boundary parameters.

[0040] The above structure ensures that the probes 111 of each probe group 11 are precisely positioned and firmly fixed, effectively resisting the thermal stress and electromagnetic force generated by plasma bombardment, and ensuring the long-term stable operation of the probe array 10 in harsh environments.

[0041] In a preferred embodiment of the present invention, in order to further improve the durability and protective capability of the graphite protective layer 30, the embodiments of the present invention have also optimized the design of the graphite protective layer 30.

[0042] Specifically, refer to Figure 2 As shown, the graphite protective layer 30 is formed by joining a first protective layer 31 and a second protective layer 32 together, with the joint between the first protective layer 31 and the second protective layer 32 adopting a stepped overlapping structure. The aforementioned stepped holes 33 can be formed on the first protective layer 31.

[0043] By adopting the above-mentioned stepped overlapping structure, the direct bombardment of plasma on the joint area between the first protective layer 31 and the second protective layer 32 can be effectively reduced, and plasma can be prevented from seeping in from the joint and causing damage to the internal structure.

[0044] Additionally, refer to Figure 3 and Figure 8 As shown, the first protective layer 31 and the second protective layer 32 of the graphite protective layer 30 are both fixedly connected to the support plate 101 of the limiter head 100 by connecting bolts 34. The graphite protective layer 30 is provided with a connecting hole 35 for accommodating the nut of the connecting bolt 34, and a graphite plug 36 for covering the nut of the connecting bolt 34 is provided in the connecting hole 35. By covering the exposed nut of the connecting bolt 34 with the graphite plug 36, the direct bombardment of the metal nut by the plasma is avoided, and impurities that may be generated after the nut is heated are prevented from contaminating the plasma environment, further improving the durability and operational safety of the overall structure.

[0045] In a preferred embodiment of the present invention, multiple probe groups 11 in the probe array 10 can be uniformly arranged along the length direction of the limiter head 100 at a preset spacing to achieve radial distribution measurement of plasma boundary parameters. Specifically, multiple probe groups 11 are arranged at equal intervals along the length direction of the mounting bracket 102, and the spacing between adjacent probe groups 11 can be 8 mm, thereby obtaining plasma boundary parameter data with sufficient spatial resolution.

[0046] Depending on the experimental purpose and measurement requirements, the probe array 10 can be flexibly configured into single-probe mode or dual-probe mode.

[0047] In single-probe mode, each probe 111 in probe array 10 operates independently. By applying a scanning voltage to probe 111, the current-voltage characteristic curve of probe 111 as a function of voltage is measured, i.e., IV.D Curve, I represents the current of probe 111, V D The voltage of probe 111 is shown. This curve includes the saturated ion flow region, the transition region, and the electron saturation flow region. In the saturated ion flow region, the voltage V of probe 111 is shown. D Much lower than the plasma space potential V p Electrons are completely blocked, and the current I of probe 111 is equal to the ion saturation current I. is In the transition region, the voltage V of probe 111 D Approximate plasma space potential V p The current I of probe 111 increases exponentially; in the electron saturation region, the voltage V of probe 111... D Greater than or equal to plasma space potential V p The electrons are almost completely absorbed by probe 111, and the current I of probe 111 is equal to the electron saturation current I. es .

[0048] In the transition region, the relationship between the current and voltage of probe 111 satisfies the following formula: ; In the above formula, For elementary charge, Boltzmann's constant, It represents the electron temperature.

[0049] From the above formula, the electron temperature can be derived as: ; In the above formula, For electron temperature, IV D The slope of the curve at the corresponding voltage.

[0050] Electron density is determined by ion saturation current I is In reverse, it can be expressed as: ; In the above formula, For electron density, The coefficients are related to the geometry of probe 111 and the expansion of the sheath. The effective collection area of ​​probe 111 This refers to the ion mass.

[0051] Among them, the single probe mode is suitable for obtaining complete current-voltage characteristic curves, thereby obtaining parameters such as electron temperature, electron density and space potential of the plasma.

[0052] In dual-probe mode, two adjacent probes 111 are used as a pair. A scanning voltage is applied between the two probes 111 to measure the current flowing between them. IV in dual-probe mode D The curve is divided into an ion saturation region and a transition region. In the ion saturation region, the voltage V of probe 111 is... D Much greater than the plasma space potential V p Electrons are blocked, and the current I of probe 111 is equal to the ion saturation current I. is In the transition region, the process is the same as the single-probe mode described above.

[0053] At this point, the electron temperature is IV. D The slope of the curve near zero is determined and expressed as: ; In the above formula, IV D The slope of the zero point in the curve, that is The slope at that time.

[0054] Based on this, electron temperature is expressed as: .

[0055] Among them, the dual-probe mode is suitable for experimental sites that require high measurement stability.

[0056] The flexible configuration of the two modes described above enables the probe array 10 to adapt to different experimental needs, providing diverse measurement methods for plasma boundary parameter diagnosis. Example 2

[0057] Based on Embodiment 1, Embodiment 2 of the present invention provides another real-time monitoring activity limiter for a quasi-toroidal stellarator. Unlike Embodiment 1, the inventors of the present invention have discovered that, in addition to reliably monitoring plasma boundary parameters using the probe array 10 and accurately monitoring the temperature of the limiter head 100, the limiter head 100 also needs to have flexible position adjustment capabilities to adapt to the complex three-dimensional magnetic surface structure of the quasi-toroidal stellarator, while ensuring dynamic sealing and reliable operation in a vacuum environment.

[0058] Therefore, please refer to Figures 1 to 11 As shown, the limiter provided in Embodiment 2 of the present invention further includes a drive mechanism 40 and an angle adjustment structure 50 to adjust the position and angle of the limiter head 100.

[0059] Specifically, refer to Figure 1 and Figure 9As shown, the drive mechanism 40 includes a push rod 41 and a push assembly 42. The first end of the push rod 41 is connected to the limiter head 100, particularly to the support plate 101. The push assembly 42 drives the push rod 41 to reciprocate linearly in a predetermined direction. The push assembly 42 is disposed outside the vacuum chamber. By driving the push rod 41 to move in the predetermined direction, the position of the limiter head 100 within the vacuum chamber in a predetermined direction can be adjusted, thereby precisely controlling the relative position of the limiter head 100 and the plasma boundary. The predetermined direction described in this embodiment can be understood as the radial direction of the three-dimensional magnetic surface structure formed within the vacuum chamber.

[0060] To accommodate the complex three-dimensional magnetic surface structure of the quasi-toroidal stellarator and ensure that the probe array 10 on the limiter head 100 faces the plasma at the optimal pole angle, an angle adjustment structure 50 is provided at the connection between the push rod 41 and the limiter head 100. Figure 1 The angle adjustment structure 50 is used to adjust the polar angle of the limiter head 100 relative to the push rod 41.

[0061] Specifically, refer to Figure 10 and Figure 11 As shown, the angle adjustment structure 50 includes an arc-shaped channel 51 disposed at the first end of the push rod 41 and a locking bolt 52. The support plate 101 of the limiter head 100 is rotatably connected to the first end of the push rod 41 by a fixing bolt 53, allowing the limiter head 100 to rotate around the fixing bolt 53. The locking bolt 52 passes through the support plate 101 and the arc-shaped channel 51 of the limiter head 100, and is used to lock the limiter head 100 to the first end of the push rod 41. When the locking bolt 52 is loosened, the limiter head 100 can rotate along the arc-shaped channel 51 around the fixing bolt 53 to adjust the polar angle of the limiter head 100 relative to the push rod 41 within a certain angle range. For example, the polar angle of the limiter head 100 can be set to 30°.

[0062] With the above structure, the operator can adjust the limiter head 100 to the optimal polar angle according to actual needs. After adjustment, tighten the locking bolt 52 to fix the angle, thereby achieving the best match between the probe array 10 on the limiter head 100 and the plasma boundary.

[0063] In a preferred embodiment of the present invention, in order to prevent the induced current in a strong magnetic field environment from having an adverse effect on the limiter head 100, the embodiment of the present invention provides an electrical isolation structure at the connection between the push rod 41 and the limiter head 100.

[0064] Specifically, refer to Figure 10As shown, a ceramic insulating sheet 60 is provided at the connection between the first end of the push rod 41 and the support plate 101 of the limiter head 100, and ceramic insulating sleeves 70 are fitted on the screws of the fixing bolt 53 and the locking bolt 52. Specifically, the ceramic insulating sheet 60 is located between the first end of the push rod 41 and the support plate 101 of the limiter head 100.

[0065] The double insulation design of ceramic insulating sheet 60 and ceramic insulating sleeve 70 can effectively block the conduction of induced current between push rod 41 and limiter head 100, avoid the influence of electromagnetic force on the overall structure of limiter, realize electrical isolation between limiter head 100 and drive mechanism 40, and help improve the accuracy of measurement signal and the operational stability of system.

[0066] In a preferred embodiment of the present invention, reference is made to Figure 9 As shown, the drive mechanism 40 also includes a bellows 43, a loose flange 44, and a transition flange 45. The transition flange 45 is fixedly connected to the outer wall of the vacuum chamber of the quasi-annular stellarator, serving as the interface between the entire drive mechanism 40 and the vacuum chamber. One end of the bellows 43 is sealed and fixedly connected to the transition flange 45, and the other end of the bellows 43 is sealed and fixedly connected to the loose flange 44. The second end of the push rod 41 passes sequentially through the transition flange 45, the bellows 43, and the loose flange 44, and the push rod 41 is sealed and fixedly connected to the loose flange 44.

[0067] With the above structure, the bellows 43 serves as a flexible sealing element, with its internal space connected to the vacuum chamber, while the outside of the bellows 43 is the atmospheric environment. When the push rod 41 moves along with the slip-on flange 44, the bellows 43 extends and retracts accordingly, always maintaining a vacuum seal, thus realizing the dynamic sealing function of the push rod 41 in a vacuum environment.

[0068] The propulsion assembly 42 is located outside the vacuum chamber. The output end of the propulsion assembly 42 is fixedly connected to the loose flange 44 and is used to drive the loose flange 44 to reciprocate linearly in a predetermined direction, thereby driving the propulsion rod 41 to move synchronously.

[0069] Through the integrated design of the aforementioned drive mechanism 40, angle adjustment structure 50, electrical isolation structure, and dynamic vacuum sealing structure, the limiter provided in Embodiment 2 of this invention not only possesses the precise temperature monitoring and plasma boundary parameter monitoring functions described in Embodiment 1, but also allows for flexible adjustment of the position and angle of the limiter head 100 to precisely match the complex three-dimensional magnetic surface structure of the quasi-toroidal stellarator, while ensuring operational stability and the integrity of the vacuum system under high-temperature and strong magnetic field conditions. This provides reliable technical support for the steady-state operation of the quasi-toroidal stellarator and for plasma physics experimental research.

[0070] As a preferred option, continue to refer to Figure 9As shown, the propulsion assembly 42 can employ a lead screw linear mechanism, specifically comprising a lead screw 421, a movable end plate 422, two fixed end plates 423, and several guide posts 424. The two fixed end plates 423 are arranged opposite to each other and fixedly. The lead screw 421 extends in a predetermined direction and is rotatably connected to the two fixed end plates 423, allowing it to rotate around its own axis. A handwheel 425 is connected to one end of the lead screw 421 for easy operation of rotating the lead screw 421.

[0071] A movable end plate 422 is disposed between two fixed end plates 423. The movable end plate 422 has a threaded hole that mates with the lead screw 421, allowing the movable end plate 422 to be threadedly connected to the lead screw 421 via its own threaded hole. The movable end plate 422 is also connected to a loose flange 44.

[0072] Several guide posts 424 are fixedly disposed between two fixed end plates 423 and parallel to the lead screw 421. The movable end plate 422 is provided with guide holes corresponding to the guide posts 424. The guide posts 424 pass through the corresponding guide holes on the movable end plate 422 to slide with the movable end plate 422, thereby playing a guiding and limiting role.

[0073] With this configuration, when the handwheel 425 is operated to drive the lead screw 421 to rotate, based on the principle of threaded transmission, the movable end plate 422 will move along the axial direction (i.e., the predetermined direction) of the lead screw 421, thereby driving the loose flange 44 and the push rod 41 to move synchronously, thus changing the position of the limiter head 100 in the predetermined direction.

[0074] By employing a lead screw linear mechanism, the propulsion assembly 42 possesses advantages such as compact structure, smooth transmission, precise position control, and good self-locking performance. The threaded engagement between the lead screw 421 and the movable end plate 422 exhibits excellent self-locking characteristics. When the external force ceases, the movable end plate 422 can remain in its current position, maintaining the stable position of the limiter head 100 without the need for additional locking devices, thereby improving the system's reliability and ease of operation.

[0075] In a preferred embodiment of the present invention, the drive mechanism 40 further includes, for example, Figure 9 The indicator plate 46 shown is provided with scale lines extending in a predetermined direction to indicate the travel of the loop flange 44 together with the push rod 41, thereby better controlling the position of the limiter head 100 in the vacuum chamber.

[0076] Specifically, the indicator plate 46 is fixedly connected between two fixed end plates 423 and is arranged parallel to the lead screw 421. The scale lines on the indicator plate 46 are evenly distributed along a predetermined direction, and the scale values ​​correspond to the actual displacement of the limiter head 100. The movable end plate 422 directly corresponds to the indicator plate 46. When the movable end plate 422 drives the loose flange 44 to move, the movable end plate 422 aligns with the scale lines at different positions on the indicator plate 46. The operator can intuitively read the real-time displacement of the loose flange 44 and the push rod 41 by observing the relative position of the movable end plate 422 and the scale lines, thereby accurately controlling the position of the limiter head 100.

[0077] With the above settings, operators can visually monitor the real-time position of the limiter head 100, achieving precise position adjustment without the need for external measuring tools. This design is particularly suitable for experimental scenarios that require repeated adjustments to the position of the limiter head 100. Operators can quickly position the limiter head 100 to the target position based on preset scale values, greatly improving the convenience and repeatability of experimental operations.

[0078] In a preferred embodiment of the present invention, in order to reliably extract the signals collected by the probe array 10 and the armored thermocouple 20 described in Example 1 from the vacuum chamber to the external control system, while ensuring the integrity of the vacuum system and the anti-interference capability of the signal transmission, the embodiment of the present invention provides a lead wire channel on the limiter head 100. Simultaneously, a signal output port 80 is provided at the second end of the push rod 41, see... Figure 9 .

[0079] The lead wire channel passes through the interior of the push rod 41 and connects to the signal lead-out port 80, through which the signal wire connecting the probe array 10 and the armored thermocouple 20 passes.

[0080] Specifically, refer to Figure 3 and Figure 5 As shown, a square tube 105 is provided on the support plate 101. The internal channel of the square tube 105 is connected to the U-shaped groove 104 on the mounting bracket 102 and the internal channel of the push rod 41 (not shown in the figure). The U-shaped groove 104 on the mounting bracket 102, the internal channel of the square tube 105, and the internal channel of the push rod 41 together constitute the lead wire channel.

[0081] The U-shaped groove 104 of the mounting bracket 102 communicates with the mounting hole 103. With the probe array 10 assembled, the signal lines of the probes 111 are led out from the rear end of the brass pillar 112 and enter the U-shaped groove 104, see... Figure 7The signal wire of the armored thermocouple 20 is also introduced into the U-shaped groove 104. Then, the signal wire within the U-shaped groove 104 passes through the square tube 105 into the internal channel of the push rod 41, extends along the internal channel of the push rod 41 to the second end of the push rod 41, and exits from the corresponding signal lead-out port 80. Preferably, the signal lead-out port 80 adopts a vacuum feedthrough structure, which can achieve electrical lead-out of the signal wire while maintaining a vacuum seal, ensuring reliable electrical connection between the inside and outside of the vacuum chamber without disrupting the vacuum environment.

[0082] Through the aforementioned lead-in channel design, all signal lines are routed within a closed channel, effectively avoiding electromagnetic interference issues in signal transmission under strong magnetic field conditions, while ensuring the integrity of the vacuum system. The overall sealed design of the lead-in channel ensures that the signal lines, after exiting from the probe 111 and armored thermocouple 20 on the limiter head 100, sequentially pass through the U-shaped groove 104 of the mounting bracket 102, the square tube 105 of the support plate 101, and the internal channel of the push rod 41, until reaching the signal exit port 80. The entire process is conducted within a vacuum-sealed environment, eliminating the need for additional through-wall components or transition joints, simplifying the structure while improving system reliability. Furthermore, the signal exit port 80 employs a vacuum feedthrough structure, achieving electrical isolation between the vacuum environment and the atmospheric environment. This ensures that the external measurement system can stably receive signals collected by the probe array 10 and armored thermocouple 20, providing a reliable data transmission channel for plasma boundary parameter monitoring and temperature correction.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A real-time monitoring activity limiter for a quasi-circular symmetric stellarator, characterized in that, Includes the limiter head and temperature correction unit; The limiter head is located inside the vacuum chamber of the quasi-annular stellarator; the limiter head is provided with a probe array, a sheathed thermocouple, and a graphite protective layer facing the plasma inside the vacuum chamber. The graphite protective layer covers the probe array, and the probes in the probe array penetrate the surface of the graphite protective layer; the probe array is used to detect plasma boundary parameters inside the vacuum chamber. The armored thermocouple is embedded inside the graphite protective layer and is used to collect the temperature signal of the limiter head in real time. The temperature correction unit is connected to the armored thermocouple signal; the temperature correction unit is configured to: acquire the radiation intensity signal of the graphite protective layer surface collected by the external infrared temperature measuring device, calculate the emissivity of the graphite protective layer surface based on the Stefan-Boltzmann law according to the temperature signal and the radiation intensity signal, and use the calculated emissivity to correct the two-dimensional temperature distribution collected by the external infrared temperature measuring device, so as to output the corrected temperature distribution data.

2. The real-time monitoring activity limiter for a quasi-ring symmetric stellarator according to claim 1, characterized in that, The armored thermocouples are multiple and are respectively embedded in different positions of the graphite protective layer.

3. The real-time monitoring activity limiter for a quasi-circular symmetric stellarator according to claim 1, characterized in that, It also includes a drive mechanism; the drive mechanism includes a push rod and a push assembly; the first end of the push rod is connected to the head of the limiter; the push assembly is used to drive the push rod to perform reciprocating linear motion along a predetermined direction. An angle adjustment structure is provided at the connection between the push rod and the limiter head; the angle adjustment structure is used to adjust the polar angle of the limiter head relative to the push rod.

4. The real-time monitoring activity limiter for a quasi-ring symmetric stellarator according to claim 3, characterized in that, The angle adjustment structure includes an arc-shaped channel and a locking bolt disposed at the first end of the push rod; The limiter head is rotatably connected to the first end of the push rod by a fixing bolt, and the locking bolt passes through the limiter head and the arc-shaped channel to lock the limiter head to the first end of the push rod; When the locking bolt is loosened, the limiter head can rotate along the arc-shaped channel to adjust the polar angle of the limiter head relative to the push rod.

5. The real-time monitoring activity limiter for a quasi-circular symmetric stellarator according to claim 4, characterized in that, A ceramic insulating sheet is provided at the connection between the first end of the push rod and the head of the limiter, and a ceramic insulating sleeve is fitted on the screw of both the fixing bolt and the locking bolt.

6. The real-time monitoring activity limiter for a quasi-ring symmetric stellarator according to claim 3, characterized in that, The drive mechanism also includes a bellows, a loose flange, and a transition flange; The adapter flange is fixedly connected to the outer wall of the vacuum chamber; One end of the bellows is sealed and fixedly connected to the transition flange, and the other end of the bellows is sealed and fixedly connected to the loose flange. The second end of the push rod passes through the adapter flange, the bellows, and the loose flange in sequence, and the push rod and the loose flange are sealed and fixedly connected. The propulsion assembly is located outside the vacuum chamber. The output end of the propulsion assembly is fixedly connected to the slip-on flange and is used to drive the slip-on flange to reciprocate linearly in a predetermined direction, thereby driving the propulsion rod to move synchronously.

7. The real-time monitoring activity limiter for a quasi-circular symmetric stellarator according to claim 6, characterized in that, The limiter head is also provided with a lead wire channel, and the second end of the push rod is provided with a signal output port; The lead channel passes through the interior of the push rod and is connected to the signal lead-out port, allowing the signal lines connecting the probe array and the armored thermocouple to pass through.

8. The real-time monitoring activity limiter for a quasi-circular symmetric stellarator according to claim 7, characterized in that, The limiter head includes a support plate and a mounting bracket; One end of the support plate is connected to the first end of the push rod; The mounting bracket is fixedly disposed on one side of the support plate and is U-shaped; the probe array is mounted on the mounting bracket; The graphite protective layer is fixedly connected to the support plate and covers the probe array and the mounting bracket; The support plate is provided with a square tube, and the internal channel of the square tube is connected to the U-shaped groove of the mounting bracket and the internal channel of the push rod; the U-shaped groove of the mounting bracket, the internal channel of the square tube, and the internal channel of the push rod together constitute the lead wire channel.

9. The real-time monitoring activity limiter for a quasi-circular symmetric stellarator according to claim 8, characterized in that, The probe array includes multiple probe groups, and each probe group includes a probe, a brass pillar, and a ceramic sleeve. The brass post is embedded inside the ceramic sleeve, and the rear end of the probe is connected to the brass post; The mounting bracket is provided with mounting holes corresponding to the plurality of probe groups, and the mounting holes are connected to the U-shaped grooves of the mounting bracket; the ceramic sleeves of each probe group are embedded in the corresponding mounting holes; The graphite protective layer is provided with stepped holes corresponding to the plurality of probe groups. The stepped holes include a small diameter end and a large diameter end. The small diameter end penetrates the surface of the graphite protective layer, and the large diameter end mates with the ceramic sleeve. The ceramic sleeves of each probe group are simultaneously embedded in the large-diameter end of the corresponding mounting hole and the corresponding stepped hole, and the detection end of the probe of each probe group is located in the small-diameter end of the corresponding stepped hole, so that the probe is exposed to the surface of the graphite protective layer.

10. The real-time monitoring activity limiter for a quasi-ring symmetric stellarator according to claim 1, characterized in that, The graphite protective layer is formed by joining a first protective layer and a second protective layer together; the joint between the first protective layer and the second protective layer adopts a stepped overlapping structure. The graphite protective layer is fixedly connected to the head of the limiter by connecting bolts. The graphite protective layer is provided with a connecting hole for accommodating the nut of the connecting bolts. A graphite plug for covering the nut of the connecting bolts is provided in the connecting hole.

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