Plasma diagnosis system focusing optimization method, device, equipment and medium

Abstract

The invention discloses a plasma diagnosis system focusing optimization method, device, equipment and medium, and relates to the technical field of plasma diagnos.The method comprises the steps that in the Tokamak discharge process, a stable target magnetic island with invariable polar distribution is determined from a two-dimensional image sequence continuously collected by a plasma diagnosis system; switching the plasma diagnosis system to a series of different optical configurations based on prior information pre-calibrated in a laboratory environment, and calculating a quantitative evaluation index representing the distribution concentration ratio of the target magnetic island in the polar space based on the image of the target magnetic island under each optical configuration; and comparing quantitative evaluation indexes of the target magnetic island under all optical configurations, determining a target optical configuration which enables polar spatial distribution to be most concentrated, and adjusting the plasma diagnosis system to the target optical configuration, thereby realizing accurate focusing under a real plasma environment, and improving the accuracy of the plasma diagnosis system. And the physical fidelity and the spatial resolution of the plasma diagnosis system are improved.

Description

Technical Field

[0001] This invention relates to the field of plasma diagnostic technology, and specifically to a focusing optimization method, apparatus, equipment, and medium for a plasma diagnostic system. Background Technology

[0002] Electron cyclotron radiation imaging (ECEI) is one of the core diagnostic tools for studying the microstructure of temperature perturbations in tokamak plasmas. Similarly, systems such as microwave imaging reflectometers (MIR) also acquire information on plasma density perturbations through two-dimensional imaging techniques. The common goal of these two-dimensional imaging diagnostic systems is to clearly distinguish the poloidal microstructures on the plasma cross-section, thereby accurately reconstructing the spatial distribution and evolution of key physical phenomena such as turbulence, magnetic islands, or boundary local modes.

[0003] Currently, the optical focusing parameters of such systems mainly rely on two methods that are detached from the actual operating environment for preset:

[0004] 1. Theoretical optical design based on vacuum conditions: In the design phase, the plasma region is approximated as a homogeneous medium or vacuum, and the parameters of optical components are determined through theoretical calculations in order to form a theoretical "optimal focal point" on the detector.

[0005] 2. Laboratory calibration based on static environment: When the tokamak device is not discharged (vacuum or cold plasma state), mechanical adjustment is performed using a fixed calibration source, and the optical state when the image is clearest is recorded as the "mechanical focus" and directly applied in subsequent experiments.

[0006] The fundamental flaw of the aforementioned method lies in its inability to fully account for the complex influence of plasma on microwave propagation during actual discharge. The most significant factor is the refractive effect of plasma. Plasma is not a homogeneous medium; its density and magnetic field exhibit strong gradients, which significantly alter the microwave propagation path, causing it to deviate from the designed optical path. Furthermore, the dynamic evolution of the plasma boundary layer (such as the sump region), electron density fluctuations, and potential magnetic field disturbances further distort beam propagation and focusing. Therefore, the theoretically calculated "optimal focal point" and the laboratory-measured "mechanical focus" often exhibit systematic deviations from the "effective focus" that yields the clearest image in a real, dynamic plasma environment. This deviation results in an imaging resolution lower than the design specifications even when the system is mechanically "aligned," with the perturbation signal being artificially broadened and small-scale physical information lost. Summary of the Invention

[0007] The technical problem to be solved by the present invention is the decrease in spatial resolution caused by inaccurate focusing in existing plasma diagnostic systems. The purpose is to provide a focusing optimization method, device, equipment and medium for plasma diagnostic systems, thereby solving the above-mentioned problem.

[0008] This invention is achieved through the following technical solution:

[0009] In a first aspect, the present invention provides a focusing optimization method for a plasma diagnostic system, comprising:

[0010] In a laboratory environment, a two-dimensional imaging plasma diagnostic system is calibrated to obtain prior information for controlling the optical focusing position;

[0011] During the tokamak discharge process, a target magnetic island with a stable structure and an unchanged morphology in the poloidal distribution is identified from the two-dimensional image sequence continuously acquired by the plasma diagnostic system.

[0012] Based on the prior information, the plasma diagnostic system is switched to a series of different optical configurations, and images of the target magnetic island are acquired under each optical configuration;

[0013] Based on the images of the target magnetic island under each optical configuration, a quantitative evaluation index characterizing the distribution concentration of the target magnetic island in the poloidal space is calculated.

[0014] By comparing the quantitative evaluation indicators of the target magnetic island under all optical configurations, the target optical configuration that makes the poloidal spatial distribution most concentrated is determined, and the plasma diagnostic system is adjusted to the target optical configuration.

[0015] Optionally, the prior information is a set of optical configuration parameters, each optical configuration corresponding to a preset focusing position; the calibration of the two-dimensional imaging plasma diagnostic system in a laboratory environment to obtain prior information for controlling its optical focusing position includes:

[0016] In a laboratory environment, the zoom factor of the plasma diagnostic system is fixed;

[0017] By adjusting the axial position or radius of curvature of the front-end reflector group in the plasma diagnostic system, a set of optical configuration parameters is established; the focusing position corresponding to the set of optical configuration parameters covers the spatial range from the plasma core to the boundary region.

[0018] Optionally, the plasma diagnostic system is an electron cyclotron radiation imaging (ECEI) system.

[0019] Optionally, the step of calculating a quantitative evaluation index characterizing the concentration of the target magnetic island's distribution in the poloidal space based on the image of the target magnetic island under each optical configuration includes:

[0020] Based on the image sequence of the target magnetic island acquired under each optical configuration, a one-dimensional poloidal disturbance intensity profile of the target magnetic island when passing through a fixed radial channel is obtained;

[0021] Based on the one-dimensional perturbation intensity profile of the polar direction and the physical polar coordinates of each polar channel, the polar spatial variance of the target magnetic island under each optical configuration is calculated.

[0022] Optionally, the step of calculating the polar spatial variance of the target magnetic island under each optical configuration based on the one-dimensional polar perturbation intensity profile and the physical polar coordinates of each polar channel includes:

[0023] Using the perturbation intensity on each polar channel in the polar one-dimensional perturbation intensity profile as the weight, the physical polar coordinates of all polar channels are weighted and averaged to obtain the position of the polar centroid of the target magnetic island.

[0024] Calculate the squared difference between the physical polar coordinates of each polar channel and the position of the polar centroid;

[0025] Using the perturbation intensity on each pole channel in the pole one-dimensional perturbation intensity profile as the weight, the squared differences of all radial channels are weighted and averaged to obtain the pole spatial variance of the target magnetic island under each optical configuration.

[0026] Optionally, the formula for calculating the position of the pole centroid is as follows:

[0027]

[0028] in, The location of the polar centroid; Let be the physical polar coordinates of the j-th polar channel; The disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0029] Optionally, the formula for calculating the polar space variance is as follows:

[0030]

[0031] in, Let Variance be the poloidal space variance. The location of the polar centroid; Let be the physical polar coordinates of the j-th polar channel; The disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0032] In a second aspect, the present invention provides a focusing optimization device for a plasma diagnostic system, comprising:

[0033] The calibration module is used to calibrate a two-dimensional imaging plasma diagnostic system in a laboratory environment to obtain prior information for controlling the optical focusing position.

[0034] The determination module is used to determine a target magnetic island with a stable structure and an unchanged morphology in the poloidal distribution from the two-dimensional image sequence continuously acquired by the plasma diagnostic system during the tokamak discharge process.

[0035] The acquisition module is used to switch the plasma diagnostic system to a series of different optical configurations based on the prior information, and to acquire images of the target magnetic island under each optical configuration;

[0036] The calculation module is used to calculate a quantitative evaluation index characterizing the distribution concentration of the target magnetic island in the poloidal space based on the image of the target magnetic island under each optical configuration.

[0037] The comparison module is used to compare the quantitative evaluation indicators of the target magnetic island under all optical configurations, determine the target optical configuration that makes the poloidal spatial distribution most concentrated, and adjust the plasma diagnostic system to the target optical configuration.

[0038] Thirdly, the present invention provides a computer device, the computer device including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the plasma diagnostic system focusing optimization method as described in any one of the first aspects.

[0039] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, wherein a processor executes the computer program to implement the plasma diagnostic system focusing optimization method as described in any one of the first aspects.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] This application provides a focusing optimization method for a plasma diagnostic system. This method combines laboratory calibration with in-situ evaluation of the discharge process, utilizing the plasma's own signals for feedback, thus overcoming the fundamental problem of traditional static calibration parameters failing in dynamic, non-uniform plasmas. A target magnetic island with a stable structure and invariant poloidal distribution is used as the test target, and the concentration of its poloidal spatial distribution is used as a quantitative evaluation index of focusing quality, achieving an objective and physical evaluation of focusing quality. After determining the target optical configuration that maximizes the poloidal spatial distribution, the plasma diagnostic system is locked to this target optical configuration, ensuring that the system remains at the optimal focusing point, thereby maximizing the recovery of spatial resolution and physical fidelity of the imaging, and providing reliable data support for the study of plasma turbulence and macroscopic instabilities. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0043] Figure 1 A schematic flowchart of a focusing optimization method for a plasma diagnostic system provided in this application embodiment;

[0044] Figure 2 Another schematic flowchart of the focusing optimization method for the plasma diagnostic system provided in this application embodiment;

[0045] Figure 3 A schematic diagram of the poloidal spatial variance of the target magnetic island under various optical configurations, provided in the embodiments of this application;

[0046] Figure 4 This is a schematic diagram of the focusing optimization device of the plasma diagnostic system provided in the embodiments of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0048] To address the issue of reduced spatial resolution in existing plasma diagnostic systems due to inaccurate focusing, this application provides a focusing optimization method for plasma diagnostic systems. Please refer to... Figure 1 This is a schematic flowchart of the focusing optimization method for the plasma diagnostic system provided in this application embodiment. The following is a further explanation. Figure 1 The focusing optimization method of the plasma diagnostic system shown is introduced.

[0049] S1. In a laboratory environment, calibrate the two-dimensional imaging plasma diagnostic system to obtain prior information for controlling the optical focusing position.

[0050] In practical implementation, a plasma diagnostic system refers to an imaging diagnostic device deployed on a tokamak device to acquire the two-dimensional spatial distribution of internal physical parameters (such as temperature, density, and disturbances) of the plasma. Its imaging quality is affected by plasma refraction effects and is subject to identifiable localized physical disturbances. Plasma diagnostic systems can be electron cyclotron radiation imaging (ECEI) systems, microwave imaging reflectometer (MIR) systems, etc.

[0051] The laboratory environment refers to the static physical environment within the vacuum chamber of a tokamak device where high-temperature plasma discharge has not occurred, or where only background gas (such as in a vacuum or pre-filled cryogenic gas) exists. In this environment, the medium within the vacuum chamber is uniform and stable, and there are no density gradients, temperature gradients, magnetic field disturbances, or various dynamic instabilities present during actual discharge. This provides ideal conditions for precise and repeatable mechanical and geometric calibration of the plasma diagnostic system.

[0052] In one possible embodiment, the prior information is a set of optical configuration parameters, each optical configuration corresponding to a preset focus position. The specific steps of S1 include:

[0053] In a laboratory environment, the zoom factor of the plasma diagnostic system is fixed; by adjusting the axial position or radius of curvature of the front-end reflector group in the plasma diagnostic system, a set of optical configuration parameters is established; the focal position corresponding to the set of optical configuration parameters covers the spatial range from the plasma core to the boundary region.

[0054] In the specific implementation process, firstly, based on the geometry and plasma configuration of the tokamak device, the required diagnostic space range is determined, extending from the plasma core to the boundary region. Secondly, in a laboratory environment, the zoom factor of the plasma diagnostic system is fixed to ensure that the field of view remains consistent at different focusing positions.

[0055] Then, based on field-of-view locking, a calibration source is used to simulate different positions within the diagnostic space. For each simulated position, the axial position or radius of curvature of the front-end mirror assembly is adjusted using a high-precision adjustment mechanism until the calibration source appears clearest and the signal is most concentrated on the image (e.g., the point spread function is narrowest, or the pattern contrast is highest). This indicates that the system has accurately focused on that simulated position. The parameter states of the front-end mirror assembly at this point (such as axial coordinate values, driver voltage values, etc.) are recorded as an optical configuration. This process is repeated until all simulated positions are traversed, obtaining a set of optical configuration parameters corresponding to the diagnostic space, denoted as . ,in, K represents the total number of configurations. Each optical configuration It uniquely corresponds to a preset focus position.

[0056] In this embodiment, by fixing the zoom coefficient, the imaging field of view and spatial scale under all preset optical configurations are strictly consistent, fundamentally eliminating systematic errors in subsequent comparisons and making the spatial concentration indexes under different configurations directly comparable. Furthermore, the theoretically continuous focus search problem is transformed into an engineering problem of scanning within a finite, discrete, known, and precisely reproducible set of optical configurations, greatly improving the operability, repeatability, and efficiency of the optimization process. By designing the preset configuration's focus positions to systematically cover the complete diagnostic range from the plasma core to the boundary, it ensures that regardless of where the "effective focus" actually shifts in the real environment, there are always close test points in the preset set, thus avoiding the risk of optimization failure from a design perspective and improving the robustness of the method.

[0057] In one possible embodiment, the prior information is the adjustable parameter range of the front-end reflector assembly, and the specific steps of S1 include:

[0058] Based on the physical safety boundary of the adjustment mechanism of the front-end reflector group, the adjustment range of the axial position is determined; based on the diagnostic space range of the plasma diagnostic system, the reflector parameters that enable the plasma diagnostic system to achieve clear focusing on the boundary of the diagnostic space range are determined through experiments, and the adjustment range of the radius of curvature is obtained.

[0059] S2. During the tokamak discharge process, a target magnetic island with a stable structure and an unchanged morphology in the poloidal distribution is identified from the two-dimensional image sequence continuously acquired by the plasma diagnostic system.

[0060] In the specific implementation process, after the tokamak discharge enters a relatively stable flat-top phase, the data acquisition program of the plasma diagnostic system is activated. The system continuously acquires two-dimensional image sequences at a preset high frame rate, forming a dynamic dataset containing spatial dimensions (such as poloidal and radial) and temporal dimensions. When the plasma diagnostic system is an ECEI system, the two-dimensional image sequence is a two-dimensional electron cyclotron radiation image sequence, which records the spatiotemporal evolution of electron temperature (or its perturbation) on the plasma cross section in real time.

[0061] In this image sequence, the following operations are performed to determine the target magnetic island:

[0062] First, by analyzing consecutive image frames, magnetic island structures that appear as localized bright or dark spots in the images are identified due to magnetic reconnection and other reasons.

[0063] Secondly, from all the identified magnetic islands, target magnetic islands that meet the following two key stability conditions are selected:

[0064] (1) Stable structure: The duration (lifetime) of the magnetic island structure in the image sequence must exceed a preset time threshold.

[0065] (2) Unchanged polar distribution pattern: During the entire stable existence of the magnetic island structure, the intensity distribution pattern in the polar dimension (i.e., its one-dimensional cross-sectional shape) remains basically unchanged. This is confirmed by calculating the morphological similarity (such as the cross-correlation coefficient) between its one-dimensional polar cross-section and a certain reference cross-section, which is always higher than a preset similarity threshold throughout the entire period.

[0066] By selecting a target magnetic island that simultaneously satisfies the requirements of "long lifespan" and "morphological stability," it is ensured that all subsequent images acquired under different optical configurations are for the same physical structure in the same physical time period, thus laying the foundation for fair and accurate comparison of focusing quality.

[0067] S3. Based on prior information, switch the plasma diagnostic system to a series of different optical configurations and acquire images of the target magnetic island under each optical configuration.

[0068] Since there are various types of prior information, there are several ways to implement S3:

[0069] (a) Stepped switching based on optical configuration parameter set:

[0070] If the prior information is a discrete set of optical configuration parameters During the tokamak discharge process, the control unit of the plasma diagnostic system will sequentially and precisely adjust the front-end reflector group to each optical configuration according to the order of the optical configuration parameter set, and acquire the image of the target magnetic island under each optical configuration.

[0071] (ii) Continuous adjustment or intelligent search based on adjustable parameter range:

[0072] If the prior information is the adjustable parameter range [Pmin, Pmax] of the front-end reflector group, then one of the following two strategies can be adopted during the tokamak discharge process:

[0073] 1. Continuous adjustment scanning: The system's control unit continuously and uniformly adjusts the parameters of the front-end reflector group (such as axial position or radius of curvature) at a preset rate within the adjustable parameter range, thereby generating a series of different optical configurations and acquiring images of the target magnetic island under each optical configuration.

[0074] 2. Intelligent search based on optimization algorithms: The system's control unit is equipped with optimization algorithms (such as gradient descent, simplex method, etc.), using the adjustable parameter range as the search space, intelligently making decisions and jumping to the next parameter point to be tested, thereby generating a series of different optical configurations and acquiring images of the target magnetic island under each optical configuration.

[0075] S4. Based on the images of the target magnetic island under each optical configuration, calculate a quantitative evaluation index characterizing the concentration of the target magnetic island's distribution in the poloidal space.

[0076] In the specific implementation process, under each optical configuration, based on the acquired images of the target magnetic island, a quantitative evaluation index is calculated to objectively compare the focusing quality under different optical configurations. This quantitative evaluation index is used to characterize the distribution concentration of the target magnetic island in the poloidal space, and can be the poloidal space variance, poloidal space standard deviation, etc.

[0077] In one possible implementation, if the quantitative evaluation index is the polar space variance, the polar space variance is calculated as follows:

[0078] Based on the image of the target magnetic island under each optical configuration, obtain the one-dimensional polar disturbance intensity profile of the target magnetic island as it passes through each radial channel; based on the one-dimensional polar disturbance intensity profile and the physical polar coordinates of each polar channel, calculate the polar spatial variance of the target magnetic island under each optical configuration.

[0079] In the specific implementation process, firstly, the target magnetic island is obtained through a fixed radial channel ( The time slice is used to extract the radial channel. The corresponding one-dimensional polar perturbation intensity profile is denoted as j = 1, 2, ..., N, where N is the total number of poloidal channels. Simultaneously, based on the geometric calibration matrix pre-established by the plasma diagnostic system (such as the ECEI system), the fixed radial channel is obtained. The physical polar coordinates of each polar channel j in that corresponding column (Unit: meters), forming a coordinate sequence .

[0080] Then, using the perturbation intensity on each polar channel in the one-dimensional polar perturbation intensity profile as the weight, the physical polar coordinates of all polar channels are weighted and averaged to obtain the position of the polar centroid of the target magnetic island.

[0081] The formula for calculating the position of the polar centroid is as follows:

[0082]

[0083] in, The location of the polar center of mass; Let be the physical polar coordinates of the j-th polar channel; Let N be the disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0084] Finally, the squared difference between the physical polar coordinates and the position of the polar centroid of each polar channel is calculated; the squared difference of all radial channels is weighted and averaged using the perturbation intensity on each polar channel in the one-dimensional perturbation intensity profile of the polar direction as the weight, so as to obtain the polar spatial variance of the target magnetic island under each optical configuration.

[0085] The formula for calculating the polar space variance is as follows:

[0086]

[0087] in, For the polar space variance, The location of the polar center of mass; Let be the physical polar coordinates of the j-th polar channel; Let N be the disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0088] In this application, based on the one-dimensional poloidal perturbation intensity profile and physical coordinates of the target magnetic island, the poloidal spatial variance is calculated, quantitatively describing the dispersion of the magnetic island perturbation signal around its intensity centroid in the poloidal spatial coordinates. Therefore, the poloidal spatial variance is introduced. As a quantitative evaluation index of the optical focusing quality of the ECEI system, The smaller the value, the more concentrated the magnetic island disturbance is in the pole direction, and the better the focusing effect of the corresponding optical configuration at that radial position. The larger the value, the more diffuse the magnetic island disturbance is in the pole direction, and the worse the focusing effect of the corresponding optical configuration at that radial position.

[0089] S5. Compare the quantitative evaluation indicators of the target magnetic island under all optical configurations, determine the target optical configuration that makes the poloidal spatial distribution most concentrated, and adjust the plasma diagnostic system to the target optical configuration.

[0090] In the specific implementation process, S3 and S4 are executed repeatedly, switching the plasma diagnostic system to a series of different optical configurations in sequence. Repeatedly acquire perturbation images and calculate the corresponding quantitative evaluation indicators, such as epipolar spatial variance. After traversing K optical configurations, a set of quantitative evaluation indexes can be obtained, such as a variance sequence: By comparing all quantitative evaluation indicators in the quantitative evaluation indicator sequence, the quantitative evaluation indicator that makes the piriform spatial distribution most concentrated is found, and the corresponding target optical configuration is recorded. Ultimately, the plasma diagnostic system was locked onto... Configure and complete focus optimization.

[0091] When the ECEI system is at or near its optimal focusing state, signals emitted from the same magnetic island are clearly converged, forming a high-contrast, sharp-edge image at its true location. At this point, the signal intensity is highly concentrated within a narrow spatial range in the epipolar direction, and the calculated epipolar spatial variance reaches its minimum value. When the ECEI system is defocused, signals emitted from the same magnetic island become diffuse or blurred on the detection plane, and the image is broadened in the epipolar direction. In this case, the signal intensity distribution range increases, and the calculated epipolar spatial variance increases significantly. Therefore, it is possible to find the minimum value in the variance sequence and record the corresponding target optical configuration. ,in .

[0092] Please refer to Figure 2 This is another schematic diagram of the focusing optimization method for the plasma diagnostic system provided in this application embodiment. The following uses the ECEI system and poloidal space variance as examples, combined with the attached diagram. Figure 2 The method described in this application will be further explained in detail.

[0093] Suppose a tokamak device is equipped with an ECEI system to observe temperature perturbations within the plasma. This ECEI system has a field of view covering the region from the core to the boundary, and features adjustable front-end optics that allow for changing the focus position with a fixed zoom factor.

[0094] Step 1: Laboratory calibration of the optical configuration set.

[0095] Before conducting plasma discharge experiments on the tokamak device, the ECEI system was first calibrated in a laboratory environment. Keeping the zoom factor of the ECEI system constant, 11 different focusing configurations were set by adjusting the axial position of the front-end mirror, corresponding to a focusing position gradually moving from 1.90 meters to the boundary of 2.20 meters at a step interval of 3 centimeters (0.03 meters): 1.90m, 1.93m, 1.96m, 1.99m, 2.02m, 2.05m, 2.08m, 2.11m, 2.14m, 2.17m, and 2.20m. The system parameters for each optical configuration were recorded, forming a set of optical configuration parameters. , used for subsequent scanning.

[0096] Step 2: Identify stable magnetic island disturbances.

[0097] During a typical discharge level-top phase, the ECEI system continuously acquired a sequence of two-dimensional electron cyclotron radiation images. A stable magnetic island perturbation was identified from the image sequence, with its poloidal position remaining essentially stable.

[0098] Step 3: Extract the fixed radial channel disturbance profile.

[0099] Select a time slice of the magnetic island passing through a fixed radial channel and extract its corresponding one-dimensional poloidal perturbation intensity distribution. Where N is the total number of polar channels. Simultaneously, based on the system's geometric calibration matrix, the physical polar coordinates corresponding to each channel in this column are obtained.

[0100] Step 4: Calculate the polar space variance.

[0101] Switch the optical configuration of the ECEI system to the following steps: to After each switch, the same perturbation image is repeatedly acquired, and its epipolar spatial variance is calculated. , The variance was calculated for different optical configurations at different focusing positions.

[0102] Step 5: Find the optical configuration corresponding to the minimum variance.

[0103] 11 optical configurations The values ​​are plotted as a curve, as shown in the attached figure. Figure 3 As shown, the epipolar spatial variance exhibits a trend of first decreasing and then increasing with the focal position. By comparing all values, the minimum variance is found. The corresponding target optical configuration. Figure 3 When k=7 (corresponding to a focusing position of 2.08m), Obtain the minimum value.

[0104] Step 6: Set the optimal focus configuration.

[0105] Lock the ECE1 system to This configuration represents the optimal focusing state under the current discharge conditions. The ECE1 system then continues to operate in this configuration to ensure the highest spatial resolution and image sharpness for observations of the magnetic island and other disturbances.

[0106] In summary, this application provides a focusing optimization method for a plasma diagnostic system, which achieves the following beneficial effects:

[0107] 1. This method directly utilizes temperature disturbances, such as the stable magnetic island naturally present during tokamak discharge, as a physical reference signal, and uses the concentration of the measured poloidal spatial distribution (e.g., poloidal spatial variance) as a quantitative indicator of focusing quality. When the plasma diagnostic system (such as the ECEI system) is in its optimal focusing state, the disturbance signal is most concentrated in the poloidal direction, and the corresponding poloidal variance reaches its minimum value. Therefore, by scanning multiple preset optical configurations and comparing the variance values ​​under different optical configurations, the "effective focal point" in the real plasma environment can be accurately located, thereby achieving physically optimal imaging.

[0108] 2. Since this method is entirely based on the diagnostic data of the plasma diagnostic system (such as the ECEI system), it does not require the introduction of external calibration sources or additional measurement equipment, and has good in-situ consistency and self-consistency. It fully considers the actual impact of plasma refraction effects, density gradients, and boundary dynamic changes on the microwave propagation path, overcomes the deviation between theoretical models and the real physical environment, and significantly improves the spatial resolution and physical fidelity of imaging.

[0109] 3. This method has a clear operational logic and a well-defined implementation path, providing direct and reliable guidance for the on-site commissioning and performance optimization of plasma diagnostic systems (such as ECEI systems). By selecting stable perturbations as the analysis object, the signal-to-noise ratio and the repeatability of the results are effectively improved, enhancing the practicality and robustness of the method.

[0110] Based on the same inventive concept, please refer to Figure 4 This application also provides a plasma diagnostic system focusing optimization device, the device comprising:

[0111] The calibration module is used to calibrate a two-dimensional imaging plasma diagnostic system in a laboratory environment to obtain prior information for controlling the optical focusing position.

[0112] The determination module is used to identify a target magnetic island with a stable structure and an invariant morphology in the poloidal distribution from a series of two-dimensional images continuously acquired by the plasma diagnostic system during the tokamak discharge process.

[0113] The acquisition module is used to switch the plasma diagnostic system to a series of different optical configurations based on prior information and acquire images of the target magnetic island under each optical configuration;

[0114] The calculation module is used to calculate a quantitative evaluation index characterizing the distribution concentration of the target magnetic island in the poloidal space based on the image of the target magnetic island under each optical configuration.

[0115] The comparison module is used to compare the quantitative evaluation indicators of the target magnetic island under all optical configurations, determine the target optical configuration that makes the poloidal spatial distribution most concentrated, and adjust the plasma diagnostic system to the target optical configuration.

[0116] Optionally, the prior information is a set of optical configuration parameters, each optical configuration corresponding to a preset focus position; the calibration module is specifically used for:

[0117] In a laboratory environment, the zoom factor of a fixed plasma diagnostic system is used;

[0118] By adjusting the axial position or radius of curvature of the front-end reflector group in the plasma diagnostic system, a set of optical configuration parameters is established; the focusing position corresponding to the set of optical configuration parameters covers the spatial range from the plasma core to the boundary region.

[0119] Optionally, the plasma diagnostic system is an electron cyclotron radiation imaging (ECEI) system.

[0120] Optionally, the calculation module is specifically used for:

[0121] Based on the image sequence of the target magnetic island acquired under each optical configuration, the one-dimensional polar disturbance intensity profile of the target magnetic island when passing through a fixed radial channel is obtained.

[0122] Based on the one-dimensional perturbation intensity profile of the pole and the physical pole coordinates of each pole channel, the pole spatial variance of the target magnetic island under each optical configuration is calculated.

[0123] Optionally, the calculation module is specifically used for:

[0124] Using the perturbation intensity on each polar channel in the one-dimensional polar perturbation intensity profile as the weight, the physical polar coordinates of all polar channels are weighted and averaged to obtain the position of the polar centroid of the target magnetic island.

[0125] Calculate the squared difference between the physical polar coordinates and the position of the polar centroid for each polar channel;

[0126] Using the perturbation intensity on each pole channel in the one-dimensional perturbation intensity profile as the weight, the squared differences of all radial channels are weighted and averaged to obtain the pole spatial variance of each optical configuration of the target magnetic island.

[0127] Optionally, the formula for calculating the position of the polar centroid is as follows:

[0128]

[0129] in, The location of the polar center of mass; Let be the physical polar coordinates of the j-th polar channel; Let N be the disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0130] Optionally, the formula for calculating the polar space variance is as follows:

[0131]

[0132] in, For the polar space variance, The location of the polar center of mass; Let be the physical polar coordinates of the j-th polar channel; Let N be the disturbance intensity on the j-th pole channel when the target magnetic island passes through the fixed radial channel; N is the total number of pole channels.

[0133] It should be noted that each module in the plasma diagnostic system focusing optimization device in this embodiment corresponds one-to-one with each step in the plasma diagnostic system focusing optimization method in the aforementioned embodiment. Therefore, the specific implementation of this embodiment can refer to the implementation of the aforementioned plasma diagnostic system focusing optimization method, and will not be repeated here.

[0134] Based on the same inventive concept, this application also provides a computer device, which includes a processor, a memory, and a computer program stored in the memory. The computer program is executed by the processor to implement the aforementioned plasma diagnostic system focusing optimization method.

[0135] Based on the same inventive concept, this application also provides a computer storage medium storing a computer program, which is executed by a processor to implement the aforementioned plasma diagnostic system focusing optimization method.

[0136] In some embodiments, the computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface memory, optical disk, or CD-ROM; or it may be a device including one or any combination of the above-mentioned memories. The computer may be a variety of computing devices, including smart terminals and servers.

[0137] In some embodiments, executable instructions may take the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0138] As an example, executable instructions may, but do not necessarily, correspond to files in the file system. They may be stored as part of a file that holds other programs or data, for example, in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple co-located files (e.g., a file that stores one or more modules, subroutines, or code sections).

[0139] As an example, executable instructions can be deployed to execute on a single computing device, or on multiple computing devices located in one location, or on multiple computing devices distributed across multiple locations and interconnected via a communication network.

[0140] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0141] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0142] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. 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 method of focusing optimization for a plasma diagnostic system, the method comprising: The method comprises the following steps: In a laboratory environment, calibrate a two-dimensional imaging plasma diagnostic system to obtain prior information for controlling the optical focus position; During a tokamak discharge process, determine a target magnetic island with a stable structure and a shape unchanged in the poloidal distribution from a sequence of two-dimensional images continuously collected by the plasma diagnostic system; Based on the prior information, switch the plasma diagnostic system to a series of different optical configurations, and collect images of the target magnetic island under each optical configuration; Based on the images of the target magnetic island under each optical configuration, calculate a quantitative evaluation index representing the concentration of the poloidal spatial distribution of the target magnetic island; Compare the quantitative evaluation indexes of the target magnetic island under all optical configurations to determine the target optical configuration that makes the poloidal spatial distribution most concentrated, and adjust the plasma diagnostic system to the target optical configuration.

2. The method of claim 1, wherein, The prior information is a set of optical configuration parameters, and each optical configuration corresponds to a preset focus position; The calibration of the two-dimensional imaging plasma diagnostic system in the laboratory environment to obtain the prior information for controlling the optical focus position comprises the following steps: In the laboratory environment, fix the zoom factor of the plasma diagnostic system; By adjusting the axial position or curvature radius of the front mirror group in the plasma diagnostic system, a set of optical configuration parameters is established; the focus positions corresponding to the set of optical configuration parameters cover the spatial range from the plasma core to the boundary region.

3. The method of claim 1, wherein the focusing optimization is performed by a computer system. The plasma diagnostic system is an electron cyclotron emission imaging (ECEI) system.

4. The method of claim 3, wherein the focusing optimization is performed by: The calculation of the quantitative evaluation index representing the concentration of the poloidal spatial distribution of the target magnetic island based on the images of the target magnetic island under each optical configuration comprises the following steps: Based on the image sequence of the target magnetic island collected under each optical configuration, obtain the poloidal one-dimensional perturbation intensity profile of the target magnetic island passing through a fixed radial channel; Based on the poloidal one-dimensional perturbation intensity profile and the physical poloidal coordinates of each poloidal channel, calculate the poloidal spatial variance of the target magnetic island under each optical configuration.

5. The method of claim 4, wherein the focusing optimization is performed by: The calculation of the poloidal spatial variance of the target magnetic island under each optical configuration based on the poloidal one-dimensional perturbation intensity profile and the physical poloidal coordinates of each poloidal channel comprises the following steps: Weight the physical poloidal coordinates of all poloidal channels by using the perturbation intensity on each poloidal channel in the poloidal one-dimensional perturbation intensity profile to obtain the poloidal centroid position of the target magnetic island; Calculate the square of the difference between the physical poloidal coordinates of each poloidal channel and the poloidal centroid position; Weight the square of the difference of all radial channels by using the perturbation intensity on each poloidal channel in the poloidal one-dimensional perturbation intensity profile to obtain the poloidal spatial variance of the target magnetic island under each optical configuration.

6. The method of claim 5, wherein the focusing optimization is performed by: The calculation formula of the poloidal centroid position is as follows: ； wherein, is the poloidal centroid position of the target magnetic island; is the physical poloidal coordinate of the jth poloidal pass; is the perturbation strength on the jth poloidal pass as the target magnetic island passes through the fixed radial pass; N is the total number of poloidal passes.

7. The plasma diagnostic system focusing optimization method according to claim 5, characterized in that, The calculation formula of the poloidal spatial variance is as follows: ； wherein, is the poloidal space variance, is the poloidal centroid position; is the physical poloidal coordinate of the jth poloidal pass; is the perturbation strength on the jth poloidal pass as the target magnetic island passes through the fixed radial pass; N is the total number of poloidal passes.

8. A plasma diagnostic system focusing optimization apparatus, characterized by, The method comprises the following steps: A calibration module is configured to calibrate a two-dimensional imaging plasma diagnostic system in a laboratory environment to obtain prior information for controlling the optical focus position. A determining module is configured to determine a target magnetic island which is stable in structure and invariant in poloidal distribution from a sequence of two-dimensional images continuously collected by the plasma diagnostic system during a tokamak discharge; An acquisition module is configured to switch the plasma diagnostic system to a series of different optical configurations based on the prior information, and acquire images of the target magnetic island under each optical configuration; A calculation module is configured to calculate a quantitative evaluation index representing the concentration of the target magnetic island in poloidal space based on the images of the target magnetic island under each optical configuration; A comparison module is configured to compare the quantitative evaluation indexes of the target magnetic island under all optical configurations, determine a target optical configuration that makes the poloidal space distribution most concentrated, and adjust the plasma diagnostic system to the target optical configuration.

9. A computer device, comprising: The computer device comprises a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the plasma diagnostic system focusing optimization method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the processor executes the computer program to implement the plasma diagnostic system focusing optimization method according to any one of claims 1-7.

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