A complex magnetic coil for a magnetic confinement fusion device and a system thereof
By employing a composite inverse magnetic coil system in a magnetic confinement fusion device, using the core and sheath of a coaxial coil as concentric circles and a compensation coil respectively, consistent compensation of the measurement position is achieved, solving the measurement error problem caused by magnetic leakage, improving the accuracy and linearity of inverse magnetic measurement, and enabling more accurate acquisition of plasma parameters.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWESTERN INST OF PHYSICS
- Filing Date
- 2026-04-09
- Publication Date
- 2026-07-14
AI Technical Summary
In magnetic confinement fusion devices, existing measurement methods using concentric circular coils and compensated coils suffer from magnetic leakage due to engineering errors, resulting in large errors in the measurement of inverse magnetic flux and making it difficult to accurately derive plasma parameters.
A composite reverse magnetic coil system is adopted, using the core and sheath of a coaxial coil as a concentric circular coil and a compensation coil, respectively, to ensure that the measurement positions of the two sets of coils are consistent. The concentric circular signal is compensated by the compensation coil, which reduces the workload of eddy current compensation and improves the measurement accuracy.
The compensation process has been simplified, significantly improving the accuracy and linearity of diamagnetic measurements, reducing measurement errors, and enabling more accurate derivation of key information such as plasma parameters, including poloidal specific pressure and vertical energy.
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Figure CN122393024A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of magnetic confinement technology, and in particular relates to a composite inverse magnetic coil and its system for use in magnetic confinement fusion devices. Background Technology
[0002] Due to the presence of a diamagnetic current, plasma exhibits a diamagnetic effect, an inherent property that reduces the magnetic flux passing through the plasma. In magnetic confinement fusion devices, several key plasma parameters can be derived by measuring the diamagnetic flux. However, the diamagnetic flux is typically 3 to 4 orders of magnitude smaller than the background circumferential flux. To suppress the dominant background flux, its influence needs to be subtracted.
[0003] For magnetic confinement fusion devices, there are two commonly used deduction methods, including: (1) Measurement principle of concentric circular coils The concentric coil consists of two sets of concentric circles mounted in a vacuum chamber and a bridge-type differential integrator. The basic principle is as follows: Figure 1 As shown. The system consists of two parts: a concentric circular coil composed of two poloidal magnetic flux loops surrounding the plasma, with different areas (area difference ΔS = Sout - Sin); and an electronic component, namely a differential integrator circuit. R in and C con For fixed-value resistors and capacitors, R out A resistor with an adjustable resistance value, wherein .
[0004] Dimagnetism can be obtained from the following formula:
[0005] in The dimagnetism is directly measured by concentric circular coils; The integration time constant of the differential integrator; This is the output signal of the differential integrator; and These are the area of the outer ring and the difference between the areas of the outer and inner rings, respectively. ).
[0006] However, due to factors such as installation errors, some magnetic leakage usually enters the concentric circle area, so:
[0007] in This is the desired diamagnetic signal; The leakage flux of the circumferential field coil between concentric circles; The leakage flux of the current in the central solenoid and the poloidal field coil between concentric circles; This refers to eddy current leakage flux in the conductors of the vacuum chamber walls and internal components.
[0008] (2) Measurement principle of compensation type coil The installation position of the compensation coil is the same as that of the concentric coil, the difference being that one end of the inner and outer coils is reversed, and the other end is used to draw out the voltage between the inner and outer coils, such as... Figure 2 As shown.
[0009] Similarly, the compensation flux is obtained as follows:
[0010] in To compensate for magnetic flux; The integration time constant of a conventional integrator; This is the output signal of a standard integrator.
[0011] Similar to concentric circular coils, compensation coils exhibit leakage flux. However, unlike concentric coils, compensation coils do not contain a reverse magnetic signal. Therefore:
[0012] Both concentric coils and compensated coils have been used in magnetic confinement fusion devices, but many difficulties have arisen during compensation, leading to measurement errors. Summary of the Invention
[0013] The purpose of this application is to overcome the problems of the prior art by disclosing a composite inverse magnetic coil and its system for magnetic confinement fusion devices, which reduces the workload of eddy current compensation while reducing measurement errors.
[0014] On the one hand, the objective of this application is achieved through the following technical solution: A composite inverse magnetic coil for a magnetic confinement fusion device is disclosed. The composite inverse magnetic coil uses the core and sheath of a coaxial coil as a concentric circular coil and a compensation coil, respectively, so that the measurement positions of the two sets of coils are consistent. The compensation coil is then used to compensate the concentric circular signal, thereby reducing the workload of eddy current compensation and reducing measurement error.
[0015] According to a preferred embodiment, when conducting a vacuum field experiment based on the composite reverse magnetic coil, the coefficient between the leakage flux and the coil current in the single-pass coil is calculated, including:
[0016]
[0017] in, The dimagnetism is directly measured by concentric circular coils. This represents the total change in circumferential magnetic flux. The leakage flux of the circumferential field coil between the concentric circular coils, and These represent the coefficients between the current in a single field coil and the demagnetization of the concentric circular coil and the compensating coil, respectively, where n is the number of the central solenoid and the number of field coils. Indicates the first i The current in each field coil, To compensate for the magnetic flux, This indicates the leakage flux of the circumferential field coil in the compensation coil.
[0018] According to a preferred embodiment, during a single-pass longitudinal vacuum field experiment, the leakage flux and diamagnetic flux of the field coil current are zero. The coefficient between the two longitudinal field leakage flux signals is calculated:
[0019] in, The leakage flux of the circumferential field coil between the concentric circular coils, This indicates the leakage flux of the circumferential field coil in the compensation coil.
[0020] According to a preferred embodiment, during a single-pass longitudinal vacuum field experiment...
[0021] but,
[0022] According to a preferred embodiment, since the measurement range and number of turns of the concentric coil and the compensation coil are exactly the same, k =1, = , .
[0023] According to a preferred embodiment, the composite reverse magnetic coil is made using a polyimide coaxial line.
[0024] On the other hand, this application also discloses: A composite inverse magnetic coil system for a magnetic confinement fusion device, the composite inverse magnetic coil system comprising: a front-end detector, electronic instruments, a data processing unit, and an interaction unit; The front-end detector is connected to the data processing unit via electronic instruments, and the data processing unit is connected to the interaction unit; The front-end detector uses the aforementioned composite inverse magnetic coil. The electronic instruments are used to convert the signals collected by the composite inverse magnetic coil into data and input them to the data processing unit. The data processing unit completes the inverse magnetic measurement of the magnetic confinement fusion device based on the detection signals of the front-end detector and transmits them to the interaction unit to realize data display and interaction.
[0025] According to a preferred embodiment, during the diamagnetic measurement process of the composite diamagnetic coil system: Assuming the tokamak possesses circumferential symmetry, then in a tokamak device with a stretch ratio, the vertical energy... and normalized specific pressure They are represented as follows:
[0026]
[0027] in, For plasma poloidal specific pressure, For plasma stretch ratio, For vacuum permeability, R and a These are the plasma size radius, For plasma current, It represents the circumferential magnetic field.
[0028] The aforementioned main solution and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application. Those skilled in the art, after understanding the solution of this application, will realize that there are many combinations based on the prior art and common general knowledge, all of which are technical solutions to be protected in this application, and will not be exhaustively listed here.
[0029] The beneficial effects of this application are: (1) Simplify compensation and improve accuracy: Concentric circular coils: serving as the main sensor, directly measuring the total circumferential magnetic flux change, including the plasma dimagnetic effect. However, it also contains interference signals such as longitudinal field and field coil.
[0030] Compensation coil: As a reference sensor, its special geometric design is completely consistent with that of the concentric circle coil, and it can measure the interference signal of the concentric circle signal.
[0031] Compensating concentric circular coils by using a compensation coil at the same location can improve the accuracy of diamagnetic measurements.
[0032] (2) Algorithm improvement The elongation ratio is clearly defined in the energy storage and normalized specific pressure calculation formulas. The coefficient formula is not negligible in tokamas with stretch ratios, especially the normalized specific pressure. ,like Figure 5 As shown. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of a concentric circle system with reverse magnetic field. Figure 2 This is a schematic diagram of a compensation coil; Figure 3 This is a schematic diagram of the composite reverse magnetic coil of this application; Figure 4 This is a schematic diagram of the composite reverse magnetic coil system of this application; Figure 5 This is a schematic diagram illustrating the effect of the elongation ratio on the calculation results. Detailed Implementation
[0034] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.
[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0036] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0037] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0038] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0039] Furthermore, it should be noted that unless otherwise specified in this application, the specific structures, connections, positions, power sources, etc. involved are all things that a person skilled in the art can know without creative effort based on the prior art.
[0040] Example 1 refer to Figure 1 As shown in the figure, a composite inverse magnetic coil for a magnetic confinement fusion device is illustrated. The composite inverse magnetic coil uses the core and sheath of a coaxial coil as a concentric circular coil and a compensation coil, respectively, so that the measurement positions of the two sets of coils are consistent. The compensation coil is then used to compensate the concentric circular signal, thereby reducing the workload of eddy current compensation and reducing measurement error.
[0041] Based on the aforementioned composite reverse magnetic coil, during vacuum field experiments, the coefficient between leakage flux and coil current in a single-pass coil is calculated, including:
[0042]
[0043] in, The dimagnetism is directly measured by concentric circular coils. This represents the total change in circumferential magnetic flux. The leakage flux of the circumferential field coil between the concentric circular coils, and These represent the coefficients between the current of a single field coil and the demagnetization of the concentric circular coil and the compensating coil, respectively, and can be calibrated using the current of a single field coil in a vacuum field; n is the number of the central solenoid and the number of field coils. Indicates the first i The current in each field coil, To compensate for the magnetic flux, This represents the leakage flux of the toroidal field coil within the compensation coil. Leakage flux from eddy currents in the vacuum chamber and internal components is ignored here. and .
[0044] In a single-pass longitudinal vacuum field experiment, the leakage flux and diamagnetic flux of the field coil current are 0. Calculate the coefficient between the two longitudinal field leakage flux signals:
[0045] in, The leakage flux of the circumferential field coil between the concentric circular coils, This indicates the leakage flux of the circumferential field coil in the compensation coil; Then we have:
[0046] Furthermore,
[0047] Unlike conventional compensating diamagnetic coils, as described in the literature "Jia TQ, He KY, Chen DL, et al. The measurements by diamagnetic loops in EAST[J]. Fusion engineering and design, 2022(Apr.):177.DOI:10.1016 / j.fusengdes.2022.113091", The calculation is for the coefficient between the compensation coil and a single coil, but since the two coils are measured at different locations, the coefficient does not follow the measurement. B t For linearly changing data, directly taking the average will inevitably introduce errors.
[0048] The innovation of this composite coil lies in using a coaxial polyimide transmission line to create a concentric circle with reverse magnetic field. The core of the coaxial line is then led out to create a concentric coil, and a compensation coil is made using a sheath to ensure that the measurement ranges of the two coils are completely identical. Figure 3 The use of a coaxial polyimide transmission line can resist the high temperatures in the vacuum chamber and ensure that the measurement positions of the compensation coil and the concentric coil are completely consistent. This application significantly reduces errors compared to using separate concentric coils and compensation coils. Ideally, since the measurement range and number of turns of the two systems are completely identical, then... k =1, = , Similarly, the previously ignored eddy current leakage flux can also be completely canceled out. This simplifies the compensation process and improves accuracy.
[0049] Whether the desired level can be achieved during the actual project implementation requires further experimental verification. Even if it cannot be achieved... k = 1, kThe linearity with respect to Bt is also better than that of a compensated coil alone. In summary, the composite reverse magnetic coil combines engineering simplicity with measurement advantages: it simplifies the compensation process of traditional concentric coils while significantly improving the measurement accuracy and linearity of compensated coils.
[0050] Example 2 Contramagnetic measurements are a widely used diagnostic tool in magnetically confined fusion devices, such as tokamaks and stellarators. Without needing to measure plasma temperature and density profiles, contramagnetic measurements can provide the plasma poloidal specific pressure. β p Vertical energy W dia and energy-constrained time τ E This information includes crucial parameters. These parameters are essential for analyzing plasma confinement performance and studying the impact of plasma instabilities on confinement.
[0051] Based on Example 1, this example also discloses a composite inverse magnetic coil system for a magnetic confinement fusion device. The composite inverse magnetic coil system includes: a front-end detector, electronic instruments, a data processing unit, and an interaction unit; The front-end detector is connected to the data processing unit via electronic instruments, and the data processing unit is connected to the interaction unit; The front-end detector uses the aforementioned composite inverse magnetic coil. The electronic instruments are used to convert the signals collected by the composite inverse magnetic coil into data and input them to the data processing unit. The data processing unit completes the inverse magnetic measurement of the magnetic confinement fusion device based on the detection signals of the front-end detector and transmits them to the interaction unit to realize data display and interaction.
[0052] Preferably, during the dimagnetic measurement process of the composite dimagnetic coil system: Assuming the tokamak possesses circumferential symmetry, then in a tokamak device with a stretch ratio, the vertical energy... and normalized specific pressure They are represented as follows:
[0053]
[0054] in, For plasma poloidal specific pressure, For plasma stretch ratio, For vacuum permeability, R and a These are the plasma size radius, For plasma current, It represents the circumferential magnetic field.
[0055] In tokams with a stretch ratio, the normalized specific pressure is not negligible, especially. ,like Figure 5 As shown, this embodiment clarifies the elongation ratio in the energy storage and normalized specific pressure calculation formulas. Coefficient formula.
[0056] Dimagnetic measurement is challenging and prone to large errors, but it is crucial for measuring specific pressure and energy storage in magnetic confinement fusion, and is an important part of the magnetic measurement diagnostic system. A composite compensation coil combining the concentric circle method and the compensation method can improve the accuracy of dimagnetic measurements.
[0057] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A composite diamagnetic coil for a magnetic confinement fusion device, characterized in that, The composite reverse magnetic coil uses the core and sheath of a coaxial coil as a concentric circular coil and a compensation coil, respectively, so that the measurement positions of the two sets of coils are consistent. The compensation coil is then used to compensate the concentric circular signal, thereby reducing the workload of eddy current compensation and reducing measurement error.
2. The composite diamagnetic coil for a magnetic confinement fusion device as described in claim 1, characterized in that, Based on the aforementioned composite reverse magnetic coil, during vacuum field experiments, the coefficient between leakage flux and coil current in a single-pass coil is calculated, including: in, The dimagnetism is directly measured by concentric circular coils. This represents the total change in circumferential magnetic flux. The leakage flux of the circumferential field coil between the concentric circular coils, and These represent the coefficients between the current in a single field coil and the demagnetization of the concentric circular coil and the compensating coil, respectively, where n is the number of the central solenoid and the number of field coils. Indicates the first i The current in each field coil, To compensate for the magnetic flux, This indicates the leakage flux of the circumferential field coil in the compensation coil.
3. The composite diamagnetic coil for a magnetic confinement fusion device as described in claim 2, characterized in that, In a single-pass longitudinal vacuum field experiment, the leakage flux and diamagnetic flux of the field coil current are 0. Calculate the coefficient between the two longitudinal field leakage flux signals: in, The leakage flux of the circumferential field coil between the concentric circular coils, This indicates the leakage flux of the circumferential field coil in the compensation coil.
4. The composite diamagnetic coil for a magnetic confinement fusion device as described in claim 3, characterized in that, During a single-pass longitudinal vacuum field experiment, but, 。 5. The composite diamagnetic coil for a magnetic confinement fusion device as described in claim 4, characterized in that, Since the measurement range and number of turns of the concentric coil and the compensation coil are exactly the same, k =1, = , .
6. The composite diamagnetic coil for a magnetic confinement fusion device as described in claim 1, characterized in that, The composite reverse magnetic coil is made using a polyimide coaxial line.
7. A composite diamagnetic coil system for a magnetic confinement fusion device, characterized in that, The composite reverse magnetic coil system includes: a front-end detector, electronic instruments, a data processing unit, and an interaction unit; The front-end detector is connected to the data processing unit via electronic instruments, and the data processing unit is connected to the interaction unit; The front-end detector employs a composite inverse magnetic coil as described in any one of claims 1 to 6. The electronic instruments are used to convert the signals collected by the composite inverse magnetic coil into data and input them to the data processing unit. The data processing unit performs inverse magnetic measurement of the magnetic confinement fusion device based on the detection signals from the front-end detector and transmits the data to the interaction unit to realize data display and interaction.
8. The composite diamagnetic coil system for a magnetic confinement fusion device as described in claim 7, characterized in that, During the dimagnetic measurement process of the composite dimagnetic coil system: Assuming the tokamak possesses circumferential symmetry, then in a tokamak device with a stretch ratio, the vertical energy... and normalized specific pressure They are represented as follows: in, For plasma poloidal specific pressure, For plasma stretch ratio, For vacuum permeability, R and a These are the plasma size radius, For plasma current, It represents the circumferential magnetic field.