Diagnostic method and system for measuring quasi-cyclic symmetric pseudostarlet electron temperature

Abstract

The present application relates to the technical field of electronic temperature diagnosis, and provides a diagnosis method and system for measuring quasi-circular symmetric stellarator electronic temperature, which comprises establishing a correlation between radiation frequency and spatial position, focusing the plasma microwave radiation into a Gaussian beam through a mirror group and focusing it on the core of the plasma, matching a complex three-dimensional magnetic field; determining an effective measurement range by calculation, so that the Gaussian beam accurately covers the range, and improving the resolution by beam focusing; completing diagnosis full-link calibration by using a blackbody source, establishing a quantitative corresponding relationship between the radiation signal intensity and the electronic temperature, and inversely calculating the electronic temperature distribution in multiple dimensions; layering the electronic module into a radio frequency part and an intermediate frequency part, processing the signal through multi-stage filtering and low-noise amplification, matching an adaptive waveguide tube to reduce the loss, and adding a data verification step to ensure the reliability of the measurement data.

Description

Technical Field

[0001] This invention relates to the field of electronic temperature diagnostics, and more specifically, to a diagnostic method and system for measuring the electronic temperature of 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 controlled magnetic confinement fusion plasma experiments, the electron cyclotron emission (ECE) diagnostic system is a core diagnostic tool. It directly measures the plasma electron temperature and its fluctuations, i.e., performs high-temperature radiation measurements, providing crucial data support for fusion physics research. The China First Quasi-axisymmetric Stellarator (CFQS) possesses a complex three-dimensional magnetic field configuration, and its plasma behavior differs significantly from that of traditional axisymmetric tokamaks. This places special demands on the spatial resolution, polarization receiving characteristics, and magnetic field configuration matching of the ECE diagnostic system. It must achieve high-precision real-time measurement of the electron temperature profile to provide feedback for plasma control, while also adapting to the stellarator's unique magnetic field structure.

[0004] In existing technologies, ECE diagnostic techniques developed based on tokamaks suffer from several technical defects when applied to CFQS: First, the three-dimensional twisted magnetic surface of the stellarator complicates the radiation propagation path, making it difficult to effectively match traditional optics and antenna layouts, easily leading to signal attenuation and polarization mismatch, affecting measurement accuracy. Second, limitations imposed by the optical field of view, diffraction limit, and detection channel make it difficult to achieve both full cross-sectional coverage and high spatial resolution in three-dimensional configurations. Third, polarization-resolved measurements are not fully realized, failing to adapt to the dynamic changes in radiation polarization states in three-dimensional magnetic fields, affecting the accuracy of electron temperature inversion. Fourth, existing inversion algorithms are based on the assumption of a two-dimensional axisymmetric magnetic field, failing to consider ray bending and multipath effects in three-dimensional configurations, resulting in systematic errors in the inversion results. Furthermore, existing technologies lack sufficient ability to suppress interference from electron cyclotron resonance heating and measure low-noise, weak signals; related performance metrics, such as decibels, gigahertz, milliseconds, and kiloelectron volts (keV), are all unsuitable for CFQS design parameters.

[0005] In summary, existing ECE diagnostic technologies suffer from systemic defects such as poor three-dimensional magnetic field configuration adaptability, difficulty in balancing spatial coverage and resolution, mismatch between polarization measurement and inversion algorithms, and insufficient anti-interference and low-noise performance, thus failing to provide reliable high-precision electronic temperature measurement data for CFQS devices. Summary of the Invention

[0006] The purpose of this invention is to provide a diagnostic method and system for measuring the electron temperature of a quasi-toroidal stellarator, thereby improving the aforementioned problems. To achieve the above objective, the technical solution adopted by this invention is as follows: In a first aspect, this application provides a diagnostic method for measuring the electron temperature of a quasi-ring-symmetric stellarator, implemented based on an electron cyclotron radiation diagnostic system. The electron cyclotron radiation diagnostic system includes a quasi-optical module, a waveguide, an electronics module, and a blackbody source. The quasi-optical module comprises two sets of metal mirrors symmetrically distributed vertically, defined as a first mirror set and a second mirror set, respectively. The signal output terminals of the first and second mirror sets are connected to the electronics module via the waveguide. The method includes: Based on the core electron temperature, electron density, small radius, and circumferential magnetic field strength parameters of the plasma in the quasi-toroidal stellarator, the radial distribution of the electron second cyclotron radiation frequency is obtained, and the correlation between the radiation frequency and the radiation spatial location is obtained; according to the range of the electron second cyclotron radiation frequency, the working frequency band for diagnostic signal transmission is determined. Based on the formula relating optical thickness and spatial radius, the effective measurement range that satisfies the optical thickness condition is calculated. The spontaneous microwave radiation signal from the plasma in the stellarator is focused by the first reflector group set in the stellarator diagnostic window to form a collimated Gaussian beam. The Gaussian beam enters the electronics module through a waveguide. The focusing position of the Gaussian beam is set at the plasma core, and the beam covers the effective measurement range. The calibration radiation signal from the blackbody source is received by the second set of mirrors and transmitted to the electronics module to calibrate the entire transmission link of the diagnostic signal. Based on the calibration results and the standard temperature characteristics of the blackbody source, combined with the blackbody radiation law of plasma electron cyclotron radiation, the quantitative correspondence between the intensity of the radiation signal obtained by diagnosis and the temperature of plasma electrons is determined. The signal within the working frequency band is down-converted, amplified, filtered, detected, and digitized using an electronics module to extract the intensity information of the target radiated signal. Based on correlation, correspondence and target radiation signal intensity information, the electron temperature and its spatial distribution data of the quasi-annular stellarator plasma within the effective measurement range are retrieved. Determine whether the plasma electron temperature and its spatial distribution data obtained from the inversion are within the preset requirements. If they are not within the preset requirements, the plasma confinement state is identified as abnormal, and the corresponding electron temperature abnormality diagnosis result is output.

[0007] Furthermore, the operating frequency band is U-band microwave.

[0008] Furthermore, the first and second reflector groups are made of polytetrafluoroethylene.

[0009] Furthermore, the spontaneous microwave radiation signal from the plasma in the stellarator is focused, specifically including: By scanning the focal length used for focusing using a preset formula, the correspondence between the emission distance and the focal length is obtained. Based on this correspondence, the focal length parameters of the Gaussian beam focusing position are matched and set so that the Gaussian beam is focused on the plasma core. The preset formula is: in, The launch distance; Focal length; The incident distance; Let be the Rayleigh length at the incident end.

[0010] Furthermore, the receiving antenna of the electronics module is a polarized antenna.

[0011] Furthermore, the receiving antenna receives microwave radiation signals from the planar region of the stellarator, and the receiving antenna is at a preset distance from the plasma magnetic axis to avoid interference from the Doppler frequency shift effect on the measurement results.

[0012] Secondly, this application also provides a diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator, comprising: The quasi-optical module contains two sets of metal mirrors that are symmetrically distributed vertically. The two sets of metal mirrors are defined as the first mirror set and the second mirror set, respectively. The signal output terminals of the first mirror set and the second mirror set are connected to the electronics module through waveguides. The waveguide has two input ports for receiving the first and second reflector groups respectively, and the output port of the waveguide is connected to the electronics module. The waveguide uses a U-band rectangular waveguide as the main transmission waveguide and is configured with a U-band linear transition waveguide as the waveguide transition section. The electronics module includes a radio frequency (RF) section and an intermediate frequency (IF) section. The RF section includes an antenna, a first filter, a second filter, a limiter, an RF isolator, a first mixer, a third filter, and a first amplifier connected in sequence. The first mixer is also connected to a voltage-controlled oscillator (VCO). The IF section includes a power divider, multiple parallel links, and an acquisition module connected in sequence. Each parallel link includes a fourth filter, a second amplifier, a second mixer, a variable attenuator, a fifth filter, a detector, a sixth filter, and a third amplifier. The second mixer is also connected to a local oscillator, and the output of the third amplifier is connected to the acquisition module. The blackbody source is directly opposite the second set of mirrors. The signal emitted by the blackbody source is input to the waveguide through the second set of mirrors.

[0013] Furthermore, the waveguide is equipped with a mode groove waveguide adapted to the electron cyclotron radiation frequency.

[0014] Furthermore, the effective receiving diameter of the metal mirror assembly of the quasi-optical module is set to be three times the width of the Gaussian beam waist of the plasma core.

[0015] Furthermore, the electronics module adopts a heterodyne receiver and has reserved an expansion interface for a superheterodyne receiver.

[0016] The beneficial effects of this invention are as follows: This invention establishes a correlation between radiation frequency and spatial position based on the core physical parameters of stellarator plasma and determines the suitable operating frequency band. Simultaneously, the quasi-optical module is designed as a symmetrical metal mirror group, allowing the first mirror group to focus the plasma microwave radiation signal into a Gaussian beam with the focal point located at the plasma core. This ensures the beam matches the plasma distribution characteristics under a three-dimensional magnetic field, matching signal reception and transmission to the complex three-dimensional magnetic field configuration, thus guaranteeing effective signal reception. Addressing the challenge of balancing spatial coverage and resolution, the effective measurement range is determined through the correlation calculation between optical thickness and spatial range, allowing the Gaussian beam to accurately cover this range. Simultaneously, the focusing effect of the mirror group improves spatial resolution while achieving full spatial coverage of the effective range. To resolve the mismatch between polarization measurement and the inversion algorithm, a blackbody source is used for full-link diagnostic calibration via a second mirror group. A quantitative correspondence between radiation signal intensity and electron temperature is established based on blackbody radiation laws. Then, relying on the frequency-position correlation and this quantitative relationship, the temperature distribution is inverted using the target signal intensity, ensuring precise matching between the inversion algorithm and polarization measurement characteristics, thereby improving inversion accuracy. To address the issues of insufficient anti-interference and low-noise performance, the electronics module is designed in layers, consisting of an RF section and an IF section. Through multi-stage filtering, low-noise amplification, and multiple parallel links, the signal is processed with precision. Combined with a suitable waveguide to reduce transmission loss, noise is suppressed and interference is resisted throughout the entire process, effectively extracting weak signals. At the same time, a data verification step is set up to identify plasma confinement anomalies in a timely manner, further ensuring the reliability of the measurement data. Attached Figure Description

[0017] Figure 1 A flowchart of a diagnostic method for measuring the electronic temperature of a quasi-ring symmetric stellarator provided by the present invention; Figure 2 This is a schematic diagram illustrating the diagnostic principle of the present invention; Figure 3 This is the secondary cyclotron radiation frequency distribution of the diagnostic window of the quasi-ring symmetric stellarator in this invention; Figure 4 This is a typical secondary unusual wave optical thickness distribution in the quasi-ring symmetric stellarator of this invention; Figure 5 This refers to the boundary of the planar plasma and the Gaussian beam distribution within the diagnostic window of the quasi-annular stellarator in this invention. Figure 6 The radial distribution of the Gaussian beam waist in this invention; Figure 7 This is a schematic diagram illustrating the relationship between the emission distance and the focal length in this invention; Figure 8 This is a schematic diagram illustrating the relationship between the waist width and focal length in this invention; Figure 9 This is a schematic diagram of the secondary cyclotron radiation signal processing principle of the electron cyclotron radiation diagnostic electronics system in this invention; Figure 10 This is a structural diagram illustrating a specific implementation of electron cyclotron radiation diagnosis in this invention; Figure 11 This invention provides a structural diagram of a diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator.

[0018] Reference numerals: 1. Diagnostic window; 2. Quasi-optical module; 21. First reflector group; 22. Second reflector group; 3. Waveguide; 4. Electronics module; 41. Radio frequency section; 411. Antenna; 412. First filter; 413. Second filter; 414. Limiter; 415. Radio frequency isolator; 416. First mixer; 417. Third filter; 418. First amplifier; 419. Voltage-controlled oscillator; 42. Intermediate frequency section; 421. Power divider; 422. Fourth filter; 423. Second amplifier; 424. Second mixer; 425. Variable attenuator; 426. Fifth filter; 427. Detector; 428. Sixth filter; 429. Third amplifier; 430. Local oscillator source; 431. Acquisition module; 5. Blackbody source. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Example 1:

[0020] like Figure 1 As shown in the embodiment of the present invention, a diagnostic method for measuring the electron temperature of a quasi-ring-symmetric stellarator is proposed. This method is implemented based on an electron cyclotron radiation diagnostic system, which takes the electron cyclotron radiation measurement principle as its core and adapts to the three-dimensional complex magnetic field configuration of the quasi-ring-symmetric stellarator, providing hardware support for high-precision measurement of plasma electron temperature. The electron cyclotron radiation diagnostic system includes a quasi-optical module 2, a waveguide 3, an electronics module 4, and a blackbody source 5, as shown in the figure. Figure 2As shown, the quasi-optical module 2 is the core of the system's front-end signal receiving, responsible for collecting and beamforming the spontaneous microwave radiation signal from the plasma; the waveguide 3 is the signal transmission link, enabling low-loss and low-interference transmission of microwave signals; the electronics module 4 is the core of signal processing, completing the frequency conversion, acquisition, and digital conversion of high-frequency microwave signals; and the blackbody source 5 is the system calibration reference, used to achieve quantitative conversion from radiation intensity to electron temperature. These four components work together to form a complete measurement and calibration link, ensuring the accuracy and reliability of diagnostic data. The quasi-optical module 2 includes two sets of symmetrically distributed metal mirrors, defined as the first mirror group 21 and the second mirror group 22. This symmetrical dual-mirror layout can match the radiation propagation path under the three-dimensional magnetic field of the stellarator, achieving uniform focusing of the Gaussian beam within the plasma measurement range and ensuring consistent poloidal resolution across the entire radial range. Simultaneously, the two mirror groups independently match the measurement and calibration optical paths, avoiding signal crosstalk and improving measurement and calibration accuracy. The signal output terminals of the first reflector group 21 and the second reflector group 22 are connected to the electronics module 4 through the waveguide 3. This connection method allows the collimated Gaussian beams shaped by the two reflector groups to be fed into the electronics module 4 with low transmission loss. At the same time, the electromagnetic shielding characteristics of the waveguide 3 suppress electromagnetic interference at the device site, ensuring the signal-to-noise ratio of the weak electron cyclotron radiation signal and providing high-quality input for back-end signal processing.

[0021] The diagnostic method specifically includes: S101, based on the core electron temperature, electron density, small radius, and circumferential magnetic field strength parameters of the plasma in the quasi-ring symmetric stellarator, obtains the radial distribution of the electron second cyclotron radiation frequency and obtains the correlation between the radiation frequency and the radiation spatial position; according to the range of the electron second cyclotron radiation frequency, the working frequency band for diagnostic signal transmission is determined.

[0022] Specifically, the frequency of the second cyclotron radiation It is calculated using the following formula: (1) In the formula, It is electric charge; For electronic quality; denoted as , where is the magnetic field strength.

[0023] Based on this formula, the radial frequency distribution of the second cyclotron radiation of the planar plasma in the CFQS quasi-toroidal stellarator can be calculated, such as... Figure 3 As shown, a one-to-one correspondence between radiation frequency and radiation spatial location is established.

[0024] Depend on Figure 3It is known that the frequency of ECE electron second harmonic radiation in the quasi-ring symmetric stellarator obtained by CFQS for the optical thickness of the plasma for the second harmonic of electron cyclotron is 44-60 GHz. Based on this range, the working frequency band for diagnostic signal transmission is determined to be U-band microwave.

[0025] S102, calculate the effective measurement range that meets the optical thickness condition based on the formula relating optical thickness and spatial radius.

[0026] Specifically, optical thickness It is a core physical quantity characterizing the absorption and emission capability of magnetized plasma for specific harmonic electron cyclotron radiation. Its value directly determines the applicable boundary of the blackbody radiation law during electron cyclotron radiation transmission. By establishing a quantitative correlation between optical thickness and the radial spatial position of the plasma, the radial range that meets the physical premise of quantitative measurement of electron temperature can be accurately screened, thus avoiding systematic errors in electron temperature inversion caused by failure to meet measurement conditions from the source. The formula relating optical thickness and spatial radius used in this step is as follows: (2) In the formula, For optical thickness, For plasma with large radius, For plasma with small radius, The magnetic flux density at the geometric center of the plasma cross section. For electron density, For harmonic order, Boltzmann's constant, The electron temperature at radial position r is... The frequency of electron cyclotron radiation. For plasma frequency, The speed of light in a vacuum. For electronic quality, Let be the magnetic flux density at the radial position r.

[0027] This formula considers the radial gradient distribution of the magnetic field and the spatial variation characteristics of plasma parameters under the three-dimensional magnetic field configuration of a quasi-toroidal stellarator. Unlike the optical thickness calculation model under the traditional two-dimensional axisymmetric assumption of a tokamak, it is adapted to the complex magnetic field environment of a quasi-toroidal stellarator CFQS, ensuring a high degree of consistency between the calculated optical thickness and the actual plasma state of the device. This provides an accurate and reliable calculation basis for determining the effective measurement range. In this step, the core criterion for effective measurement is set as the plasma optical thickness at the target diagnostic location under 1T operating conditions. >2, when optical thickness When the value is greater than 2, the plasma at that radial position is in an optically thick state for the electron cyclotron radiation at the corresponding frequency. At this time, the electron cyclotron radiation frequency is in the microwave band, satisfying the Rayleigh-Jeans limit. Its radiation intensity can be accurately described by the blackbody radiation formula, which is: (3) In the formula, Radiation intensity; Boltzmann's constant; It represents the electron temperature.

[0028] Furthermore, under non-relativistic conditions and with electron velocities exhibiting a Maxwell distribution, the intensity of electron cyclotron radiation is strictly linearly proportional to electron temperature. This relationship is the core physical premise for this diagnostic method to invert electron temperature through radiation intensity. The criterion of >2 allows for the rigorous screening of radial regions where quantitative and accurate measurement of electron temperature can be achieved, excluding regions with insufficient optical thickness or where the radiation intensity and electron temperature do not satisfy a linear proportional relationship. This avoids data distortion from a physical perspective, ensuring the accuracy of diagnostic results. In this step, the rated design parameters of the CFQS quasi-ring symmetric stellarator are substituted into the aforementioned optical thickness calculation formula, where the plasma core electron temperature... 2keV, electron density 2×10 19 m -3 small radius The circumferential magnetic field strength is 0.315m. For 1T, harmonic order Taking 2, the plasma's different radial radii are calculated point by point. Optical thickness corresponding to the position Numerical values ​​are obtained to determine the distribution of optical thickness along the plasma radial direction. By substituting the rated design parameters of the actual operation of the device, the spatial distribution of optical thickness under typical discharge conditions can be simulated. This ensures that the calculated effective measurement range can cover the plasma parameter range of conventional physics experiments, fully meeting the diagnostic requirements of CFQS quasi-ring symmetric stellarator physics experiments. Finally, based on the calculated radial distribution of optical thickness, all parameters that meet the requirements are selected. The radial position interval of condition >2 is the effective measurement range of the diagnostic system. For the typical operating conditions of the CFQS quasi-annular symmetric stellarator, calculations were performed to obtain the condition that satisfies... The spatial range of >2 has a large radius R of 60cm to 100cm, such as Figure 4As shown, this interval is the effective measurement range of the diagnostic system. All radial positions within this interval meet the optical thickness condition, and the electron temperature can be accurately inverted through the radiation intensity of the corresponding frequency. This not only clarifies the radial measurement boundary of the diagnostic system, but also provides the core design input for the parameter design of the diagnostic system hardware module. At the same time, it ensures that the electron temperature data output by the diagnostic system has a reliable physical basis and stable measurement accuracy within this effective measurement range.

[0029] S103, by using the first reflector group 21 set in the stellarator diagnostic window 1, the spontaneous microwave radiation signal of the plasma in the stellarator is focused to form a collimated Gaussian beam. The Gaussian beam enters the electronics module 4 through the waveguide 3. The focusing position of the Gaussian beam is set at the plasma core, and the beam covers the effective measurement range.

[0030] Specifically, the first reflector group 21, located in the quasi-annular stellarator at the diagnostic window 1 (plane 8), focuses the spontaneous microwave radiation signal from the plasma in the stellarator to form a collimated Gaussian beam. This Gaussian beam enters the electronics module 4 through the waveguide 3. The first reflector group 21 belongs to the quasi-optical module 2 of the diagnostic system and is the core component for front-end signal reception in the system's measurement optical path. It is located at the diagnostic window 1 and can directly face the plasma radiation area. The receiving antenna in the electronics module 4 is approximately 0.85 meters away from the plasma magnetic axis. The receiving antenna is a polarized antenna, which can directionally receive the microwave radiation signal from the planar region in the stellarator. This avoids the Doppler frequency shift interference caused by non-planar signal reception from the signal reception source, ensuring the accuracy of the one-to-one correspondence between radiation frequency and radiation spatial position established in step S101.

[0031] The microwave signal of the corresponding frequency spontaneously emitted by electrons in the plasma during their cyclotron motion is the core signal carrier for electron temperature measurement. The first reflector group 21 can efficiently collect this weak microwave radiation signal. At the same time, based on the Gaussian beam transmission theory, the collected signal is focused and beam shaped to convert the spherical waves radiated from different radial positions of the plasma into collimated Gaussian beams that meet the requirements of the back-end transmission. The transmission characteristics of this beam can be designed using the following formula: (4) (5) (6) (7) (8) In the formula, The width of the waistband; For antenna output beam; The distance from the waistband; Rayleigh length; Let be the Rayleigh length at the incident end; Wavelength; The incident distance; The launch distance; Focal length; For incident waist; For launching; The radius of curvature of the mirror group in quasi-optical module 2.

[0032] The relationship between the beam waist width and the transmission distance satisfies Formula 4, and the relationship between the Rayleigh length and the beam waist width satisfies Formula 5. Through this optical transformation, the beam can maintain energy concentration during transmission, significantly reducing signal transmission loss caused by beam divergence. At the same time, it ensures that the shaped beam mode is precisely matched with the input mode of the back-end waveguide 3, ensuring that the collimated Gaussian beam can be fed into the electronics module 4 through the waveguide 3 with low transmission loss. The electromagnetic shielding characteristics of the waveguide 3 itself can simultaneously suppress strong electromagnetic interference at the fusion device site, ensuring the signal-to-noise ratio of the weak electron cyclotron radiation signal transmission, and providing a high-quality input signal for the signal processing of the back-end electronics module 4. The Gaussian beam is focused at the plasma core, covering the effective measurement range. This focus point is the core region of the CFQS quasi-toroidal stellarator plasma, and also the center of the effective measurement range determined in step S102. Based on the Gaussian beam transmission characteristics described in formulas 4 and 5, focusing at the plasma core minimizes the beam waist width variation across the entire effective measurement range, achieving uniform focusing of the Gaussian beam within the plasma's effective measurement range and ensuring consistent poloidal resolution across the entire radial measurement interval. In specific implementation, based on the design conditions of approximately 0.8m from the plasma core to the quasi-optical system, a weak-field side boundary radius of 1.122m, a strong-field side boundary radius of 0.575m, and an ECE second cyclotron center frequency of 52GHz, the corresponding calculations using formulas 4 to 8 yield a Gaussian beam waist width of 3.1cm, with its radial distribution as shown below. Figure 5 As shown, the beam waist width parameter directly determines the spatial focusing capability of the beam. A core beam waist width of 3.1 cm allows the beam to be within the effective measurement range of 60 cm to 100 cm determined in step S102. The fluctuation range of the beam waist width is controlled within the design allowable range, ultimately achieving a uniform poloidal resolution of approximately 6 cm for the designed Gaussian beam in plasma. This enables complete and efficient reception of electron cyclotron radiation signals at all radial positions within the effective measurement range, avoiding problems such as missing measurement ranges and inconsistent radial measurement accuracy caused by incomplete beam coverage and uneven resolution.

[0033] Furthermore, the spontaneous microwave radiation signal from the plasma in the stellarator is focused, specifically by scanning the focal length used for focusing using a preset formula to obtain the correspondence between the emission distance and the focal length, such as... Figure 7 As shown, the focal length parameters of the Gaussian beam focusing position are matched and set according to the corresponding relationship, so that the Gaussian beam is focused on the plasma core. The preset formula is Formula 6, which is the core transmission formula of the Gaussian beam optical system design. It is used to quantitatively describe the quantitative relationship between the output distance of the Gaussian beam after optical transformation by the reflector group and the focal length, incident distance, and Rayleigh length at the incident end. In this step, the focal length parameters of the first reflector group 21 are scanned in full range by Formula 6. The output distance variation law corresponding to different focal length values ​​can be obtained, and a one-to-one correspondence between output distance and focal length can be established. The output distance directly determines the spatial focusing position of the Gaussian beam. Therefore, based on the target output distance corresponding to the preset focusing position of the plasma core, the optimal focal length parameters can be matched in the correspondence obtained by scanning, so that the Gaussian beam can be accurately focused on the plasma core, and the beam can be stably and uniformly focused and high-resolution signal received within the effective measurement range.

[0034] Furthermore, to match the transmitting and receiving antennas, a scanning analysis of the focal length and the beam waist of the transmitting microwave is performed using Equation 7. The relationship between the beam waist width and the focal length is as follows: Figure 8 As shown. Combining the U-waveguide standard 25dBi gain pyramid antenna, the transmit beam waist is approximately 2.4cm. Therefore, when the transmit beam waist is 2.4cm, the corresponding focal length is approximately f=0.47m (…). Figure 8 At this time, the distance from the antenna to the reflector is approximately 0.65m. Figure 7 The mirror material used in this design is polytetrafluoroethylene (PTFE), whose refractive index, measured in the laboratory, is approximately n=1.6. According to the focal length formula: (9) in, where n is the focal length and n is the refractive index. is the radius of curvature and satisfies From formula (9), we can obtain Therefore, the radius of curvature of the reflector in this design is 0.564m.

[0035] S104, the calibration radiation signal from the blackbody source 5 is received through the second reflector group 22 and transmitted to the electronics module 4 to calibrate the entire link of the diagnostic signal transmission; based on the calibration results and the standard temperature characteristics of the blackbody source 5, combined with the blackbody radiation law of plasma electron cyclotron radiation, the quantitative correspondence between the intensity of the radiation signal obtained for diagnosis and the temperature of plasma electrons is determined.

[0036] Specifically, the second reflector group 22, as a dedicated signal receiving component for the calibration optical path within the quasi-optical module 2, is symmetrically distributed vertically with the first reflector group 21. This independent layout avoids crosstalk between the measurement signal and the calibration signal from the source of the optical path, ensuring the accuracy of the calibration. It receives the calibration radiation signal from the 550-degree Celsius cavity blackbody source 5 and performs focusing and beam shaping of the calibration radiation signal according to formulas 4 to 8 of Gaussian beam transmission. After converting it into a collimated Gaussian beam that matches the back-end transmission link, it transmits the signal to the electronics module 4 through the waveguide 3. The low-loss transmission characteristics of waveguide 3 can reduce the energy loss of calibration signals during transmission. At the same time, its electromagnetic shielding characteristics can suppress electromagnetic interference at the device site, ensuring that the calibration signal is transmitted to the electronics module 4 with a high signal-to-noise ratio. This transmission process covers the entire diagnostic signal transmission link from the quasi-optical module 2, waveguide 3 to the electronics module 4. Calibrating this entire link can effectively eliminate the transmission loss of each hardware module and the system error caused by the inherent response deviation of the device, laying a precise hardware foundation for the subsequent quantitative conversion of radiation signal intensity to electronic temperature.

[0037] Based on the calibration results obtained from the above full-link calibration, combined with the known standard temperature characteristics of blackbody source 5, and relying on the blackbody radiation law of plasma electron cyclotron radiation in Formula 3, the linear proportional relationship between electron cyclotron radiation intensity and electron temperature under optical thickness conditions can be used to quantify the response characteristics of the diagnostic system to radiation signals at different standard temperatures. This allows for the precise determination of the quantitative correspondence between the plasma radiation signal intensity actually acquired by the diagnostic system and the actual plasma electron temperature. This quantitative correspondence is the core basis for this diagnostic method to invert electron temperature through radiation signal intensity. Its establishment realizes the transformation from relative measurement of radiation signal intensity to absolute measurement of electron temperature, ensuring that subsequent accurate quantitative inversion from radiation signal intensity to electron temperature can be completed based on this correspondence.

[0038] S105 uses electronics module 4 to perform down-conversion, amplification, filtering, detection, and digitization on signals within the operating frequency band to extract the intensity information of the target radiation signal.

[0039] Specifically, electronics module 4 adopts a low-noise U-band multi-channel superheterodyne receiver architecture, the receiver's principle structure of which is as follows: Figure 9As shown, the electron cyclotron radiation signal, operating in the 40-60 GHz U-band, transmitted to the module via waveguide 3, undergoes end-to-end processing to accurately extract the intensity information of the target radiation signal. The mixer within the module, in conjunction with the local oscillator 430, down-converts the input high-frequency microwave signal to a more easily processed intermediate frequency (IF) range. This processing, while preserving the signal amplitude and phase information, reduces link losses and technical difficulties in high-frequency signal transmission and processing, and avoids the impact of strong electromagnetic interference in the high-frequency band on weak signals. Subsequently, the IF amplification unit linearly amplifies the mixed IF signal, increasing the signal amplitude to match the input requirements of subsequent processing stages, while controlling the RF noise figure to within 10 dB, significantly improving the signal-to-noise ratio and ensuring that the weak electron cyclotron radiation signal can be effectively captured. Next, the filter performs band selection on the amplified intermediate frequency (IF) signal, filtering out image frequencies generated by mixing, local oscillator leakage signals, out-of-band noise, and electron cyclotron resonance heating interference signals with a center frequency of 54.5 GHz and a bandwidth of 1 GHz. The attenuation of this heating interference signal is greater than 50 dB, effectively purifying the target frequency band signal and preventing clutter interference from causing system errors in subsequent signal strength extraction. Then, the detector 427 performs envelope detection on the filtered IF AC signal, converting it into a DC or low-frequency envelope signal positively correlated with the radiated power intensity. This directly extracts the amplitude information of the radiated power intensity IECE in Formula 3, realizing the conversion from a high-frequency AC signal to a quantifiable power signal. Finally, after the video amplification unit performs matched amplification on the detected signal, the analog signal is converted into a digital signal by an analog-to-digital converter, completing the digital processing of the signal. This process uses a high-impedance matched acquisition unit with a sampling rate of 1 MS / s, ensuring a time resolution of 1 ms for signal sampling. The final output is accurately quantified target radiated signal intensity information that can be used for subsequent inversion calculations.

[0040] S106, based on correlation, correspondence and target radiation signal intensity information, inverts the electron temperature and its spatial distribution data of the quasi-ring symmetric stellarator plasma within the effective measurement range.

[0041] Specifically, the correlation is the one-to-one correspondence between the electron second cyclotron radiation frequency and the radiation spatial position calculated by formula 1 in S101. This relationship provides a core positional benchmark for the inversion of the electron temperature spatial distribution. Based on this, the intensity information of each extracted target radiation signal can be accurately matched to the corresponding radial position of the plasma, clarifying the spatial coordinates corresponding to each intensity information, and laying the positional foundation for subsequent spatial distribution inversion. The correspondence is the quantitative correspondence between the radiation signal intensity and the plasma electron temperature established by S104 based on the calibration results of blackbody source 5 and the blackbody radiation law of formula 3. This relationship is based on the linear proportional relationship between radiation intensity and electron temperature under optical thickness conditions as the core physical principle. It can directly convert the quantified target radiation signal intensity information into the specific value of the electron temperature at the corresponding position, realizing the quantitative inversion from signal intensity to temperature. Combining the above two types of relationships with the target radiation signal intensity information at each radial position extracted by the electronics module 4, the plasma measurement points within the effective measurement range are inverted point by point, and finally the electron temperature value and radial spatial distribution data of the quasi-ring symmetric stellarator plasma are accurately obtained.

[0042] S107, determine whether the plasma electron temperature and its spatial distribution data obtained by inversion are within the preset requirements. If they are not within the preset requirements, the plasma confinement state is identified as abnormal, and the corresponding electron temperature abnormality diagnosis result is output.

[0043] Specifically, under normal plasma confinement conditions, the electron temperature range and radial distribution gradient of the quasi-toroidal stellarator match the rated design parameters of the device and the laws of plasma physical confinement. Based on this, a compliance judgment threshold or range is preset. The inverted electron temperature values ​​and radial spatial distribution characteristics are compared with the preset requirements (i.e., whether the compliance judgment threshold or range is met). If the data exceeds the preset requirement range, the plasma confinement state is identified as abnormal, and the corresponding electron temperature abnormality diagnosis result is output simultaneously. This can quickly locate plasma confinement failure and abnormal parameter conditions, providing a direct diagnostic basis for real-time status monitoring and safe operation of the device's physical experiments.

[0044] Example 2, as Figure 11 As shown, based on the same inventive concept, this embodiment provides a diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator. This system is applied to the diagnostic method in Embodiment 1, and includes: The quasi-optical module 2 includes two sets of metal mirrors that are symmetrically distributed vertically. The two sets of metal mirrors are defined as the first mirror group 21 and the second mirror group 22, respectively. The signal output terminals of the first mirror group 21 and the second mirror group 22 are connected to the electronics module 4 through the waveguide 3.

[0045] Specifically, the quasi-optical module 2 serves as the front-end signal receiving core of the diagnostic system. The first reflector group 21 is used to receive the signal from the stellarator. Relying on the Gaussian beam transmission characteristics of formulas (4) to (8), the Gaussian beam is uniformly focused within the plasma measurement range, thereby ensuring the consistency of the poloidal resolution across the entire radial range. The second reflector group 22 is used to receive the signal from the blackbody source 5. It is used to match the measurement optical path and the calibration optical path, avoiding crosstalk between the measurement signal and the calibration signal from the source of the optical path, effectively improving the measurement and calibration accuracy of the system. The signal output ends of the first reflector group 21 and the second reflector group 22 are connected to the electronics module 4 through the waveguide 3. This connection method can feed the collimated Gaussian beam after the two reflector groups are shaped into the electronics module 4 with low transmission loss. At the same time, by utilizing the electromagnetic shielding characteristics of the waveguide 3 itself, the strong electromagnetic interference at the fusion device site is suppressed, ensuring the transmission signal-to-noise ratio of the weak electron cyclotron radiation signal, and providing a high-quality input signal for the signal processing stage of the back-end electronics module 4.

[0046] The waveguide 3 is provided with two input ports for receiving the first reflector group 21 and the second reflector group 22 respectively. The output port of the waveguide 3 is connected to the electronics module 4. The waveguide 3 uses a U-band rectangular waveguide as the main transmission waveguide and is configured with a U-band linear transition waveguide as the waveguide transition section. The waveguide 3 is provided with a mode groove waveguide adapted to the electron cyclotron radiation frequency.

[0047] Specifically, the dual-input port design allows for independent reception of Gaussian beams transmitted from the measurement and calibration optical paths, enabling crosstalk-free and low-loss transmission of both signals. Waveguide 3 uses a U-band rectangular waveguide as the main transmission waveguide and is equipped with a U-band linear transition waveguide as a transition section. This waveguide selection and transition structure design can match the system's 40-60GHz U-band operating frequency band and adapt to the transmission requirements of the electron cyclotron radiation frequency, effectively reducing mode conversion loss of microwave signals during waveguide transmission and ensuring signal transmission integrity. In addition, waveguide 3 also includes a mode-crossing grooved waveguide adapted to the electron cyclotron radiation frequency. The mode-crossing grooved waveguide can adapt to the transmission characteristics of Gaussian beams and reduce signal loss caused by beam divergence.

[0048] Electronics module 4 includes a radio frequency (RF) section 41 and an intermediate frequency (IF) section 42. The RF section 41 includes, in sequence, an antenna 411, a first filter 412, a second filter 413, a limiter 414, an RF isolator 415, a first mixer 416, a third filter 417, and a first amplifier 418. The first mixer 416 is also connected to a voltage-controlled oscillator (VCO) 419. The IF section 42 includes, in sequence, a power divider 421, multiple parallel links, and an acquisition module 431. Each parallel link includes, in sequence, a fourth filter 422, a second amplifier 423, a second mixer 424, a variable attenuator 425, a fifth filter 426, a detector 427, a sixth filter 428, and a third amplifier 429. The second mixer 424 is also connected to a local oscillator 430, and the output of the third amplifier 429 is connected to the acquisition module 431. Its structure is as follows: Figure 10 As shown, this structure is similar to Figure 9 The structural principles are the same, the difference lies in... Figure 9 The single-channel core principle block diagram of the ECE diagnostic superheterodyne receiver clarifies the core measurement link of the ECE high-frequency radiation signal, which is processed by mixing and down-conversion, intermediate frequency amplification and filtering, detection to extract radiation power, video amplification and analog-to-digital conversion, and finally outputs a digital signal that is proportional to the electron temperature. Figure 10 This is the engineering system implementation of this core principle. Based on the complete reuse of a single-channel core link, it achieves high-precision multi-channel electron temperature measurement of the plasma radial profile through front-end anti-interference filtering, multi-channel array power division and frequency division, and low-noise and electromagnetic shielding optimization. Its specific operating principle is as follows: In the radio frequency (RF) section 41, the antenna serves as the signal input component. Through the collimated Gaussian beam transmitted via the waveguide 3, it achieves directional reception of U-band microwave signals, providing the original input signal for subsequent signal processing in the RF section 41. The first filter 412 and the second filter 413 sequentially perform band filtering on the received high-frequency microwave signal, filtering out out-of-band spurious noise and irrelevant interference signals, initially purifying the signal source and ensuring signal purity in subsequent signal processing stages. The limiter 414 suppresses sudden strong amplitude interference signals during transmission, preventing hardware damage to downstream microwave devices due to excessively strong signals and ensuring the overall stable operation of the RF section 41. The RF isolator 415 is used for unidirectional signal transmission, suppressing reflections and protecting the preceding stage. The controlled oscillator 419 provides an adjustable local oscillator signal to the first mixer 416. The first mixer 416 uses this local oscillator signal to downconvert the high-frequency U-band microwave signal to a more easily processed intermediate frequency range, reducing the technical difficulty of high-frequency signal transmission and processing, while completely preserving the amplitude and phase information of the signal and not losing the core characteristics of the target signal. The third filter 417 performs frequency band selection on the downconverted intermediate frequency signal again, accurately filtering out the image frequency interference generated during the mixing process, and further purifying the signal. The first amplifier 418 linearly amplifies the filtered intermediate frequency signal, increases the signal amplitude, and makes it match the signal input requirements of the intermediate frequency section 42, realizing signal adaptation and transmission between the radio frequency section 41 and the intermediate frequency section 42.The intermediate frequency (IF) section 42's power divider 421 evenly distributes the IF signal output from the radio frequency (RF) section 41 to multiple parallel links, enabling multi-channel synchronous signal processing. This adapts to the diagnostic system's requirement for simultaneous measurement of plasma at different radial positions, effectively improving the system's spatial measurement resolution. In each parallel link, the fourth filter 422 first performs precise band filtering on the distributed IF signal, further filtering out noise signals introduced during link transmission to ensure signal purity. The second amplifier 423 amplifies the filtered signal, ensuring sufficient amplitude for subsequent frequency conversion processing and preventing feature loss due to low signal amplitude. The local oscillator 430 provides a high-precision local oscillator signal to the second mixer 424, which uses this signal to perform secondary frequency conversion on the IF signal, ensuring precise matching of the signal bandwidth to the processing requirements of the acquisition module 431, while fully preserving the signal's amplitude characteristics, laying the foundation for subsequent radiation intensity extraction. The variable attenuator 425 flexibly adjusts the secondary frequency conversion. The amplitude of the signal is adjusted to ensure that the output signal amplitude of each parallel link remains consistent, avoiding measurement errors caused by amplitude deviation between channels and improving the consistency of multi-channel measurements. The fifth filter 426 and the sixth filter 428 sequentially perform multi-stage filtering on the signal to thoroughly filter out spurious frequencies and various interference signals generated by the secondary frequency conversion, maximizing the purity of the target signal. The detector 427 converts the filtered signal into a signal that is easy for the acquisition module 431 to measure and acquire. The third amplifier 429 performs final linear amplification on the multi-stage processed signal, so that the signal amplitude reaches the input threshold of the acquisition module 431, ensuring that the acquisition module 431 can effectively identify and acquire the signal. The acquisition module 431, as the signal output component of the intermediate frequency section 42, completes the digital conversion from analog to digital signals. It adopts a high-impedance matching design with a sampling rate of 1MS / s to ensure that the time resolution of signal sampling can reach 1ms. The final output can be directly used for precise quantification of target radiation signal intensity information for electron temperature inversion.

[0049] Blackbody source 5 is directly opposite the second reflector group 22. The signal emitted by blackbody source 5 is input to waveguide 3 through the second reflector group.

[0050] Specifically, the 550°C cavity blackbody source 5 can stably emit radiation signals with standard temperature characteristics. This radiation signal is focused and shaped into a collimated Gaussian beam that meets the system transmission requirements by the second reflector group 22 according to the Gaussian beam transmission characteristics of formulas 4 to 8. Then, it is transmitted completely to the electronics module 4 through the waveguide 3, thereby realizing the calibration of the entire diagnostic signal transmission link. This can effectively eliminate the system errors caused by the transmission loss of each hardware component of the quasi-optical module 2, waveguide 3, and electronics module 4, as well as the inherent response deviation of the devices. Combined with the blackbody radiation law of formula 3, the quantitative correspondence between radiation signal intensity and plasma electron temperature can be accurately established based on the calibration results, providing an accurate calibration basis for realizing the quantitative conversion of radiation intensity to electron temperature.

[0051] Furthermore, the effective receiving diameter of the metal mirror assembly of the quasi-optical module 2 is set to be three times the width of the Gaussian beam waist of the plasma core, such as... Figure 6 As shown.

[0052] Specifically, the design is based on the Gaussian beam transmission characteristics of formulas 4 to 8. According to the above formulas, the waist width of the Gaussian beam in the plasma core of the CFQS quasi-ring symmetric stellarator is 3.1 cm. The receiving diameter designed at a ratio of 3 can capture most of the Gaussian beam energy. Since the Gaussian beam energy formed by the spontaneous microwave radiation of the plasma is concentrated in the area around the waist, this size can maximize the signal receiving efficiency and reduce the signal transmission loss caused by the incomplete reception of beam energy, directly improving the signal-to-noise ratio of the received signal of the diagnostic system.

[0053] Furthermore, the electronics module 4 adopts a heterodyne receiver and has reserved an expansion interface for a superheterodyne receiver.

[0054] Specifically, the module has a reserved superheterodyne receiver expansion interface, which is compatible with multi-stage frequency conversion and multi-channel array expansion architecture, and can adapt to the diagnostic needs of higher frequency bands and higher spatial resolution in the future, thereby improving the scalability and adaptability of the system.

[0055] Furthermore, the first reflector group 21 and the second reflector group 22 are made of polytetrafluoroethylene.

[0056] Specifically, since the effective receiving diameter is set to three times the width of the Gaussian beam waist of the plasma core, the size is too large and not suitable for design using a mirror assembly in a vacuum chamber. Therefore, the quasi-optical design uses a polytetrafluoroethylene mirror to ensure low loss and high transmittance during microwave transmission, thereby improving the signal-to-noise ratio.

[0057] It should be noted that the specific methods by which each module performs operations in the system described in the above embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0058] 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 diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator, characterized in that, Based on an electron cyclotron radiation diagnostic system, the system includes a quasi-optical module, a waveguide, an electronics module, and a blackbody source. The quasi-optical module comprises two sets of symmetrically arranged metal mirrors, defined as a first mirror set and a second mirror set. The signal output terminals of the first and second mirror sets are connected to the electronics module via the waveguide. The diagnostic method includes: Based on the core electron temperature, electron density, small radius, and circumferential magnetic field strength parameters of the plasma in the quasi-toroidal stellarator, the radial distribution of the electron second cyclotron radiation frequency is obtained, and the correlation between the radiation frequency and the radiation spatial location is obtained; according to the range of the electron second cyclotron radiation frequency, the working frequency band for diagnostic signal transmission is determined. Based on the formula relating optical thickness and spatial radius, the effective measurement range that satisfies the optical thickness condition is calculated. The spontaneous microwave radiation signal from the plasma in the stellarator is focused by the first reflector group set in the stellarator diagnostic window to form a collimated Gaussian beam. The Gaussian beam enters the electronics module through a waveguide. The focusing position of the Gaussian beam is set at the plasma core, and the beam covers the effective measurement range. The calibration radiation signal from the blackbody source is received by the second reflector group and transmitted to the electronics module to calibrate the entire diagnostic signal transmission link. Based on the calibration results and the standard temperature characteristics of the blackbody source, combined with the blackbody radiation law of plasma electron cyclotron radiation, the quantitative correspondence between the intensity of the radiation signal obtained for diagnosis and the plasma electron temperature is determined. The electronic module performs down-conversion, amplification, filtering, detection, and digitization on the signal within the operating frequency band to extract the intensity information of the target radiation signal. Based on the aforementioned correlation, correspondence, and target radiation signal intensity information, the electron temperature and its spatial distribution data of the quasi-annular stellarator plasma within the effective measurement range are retrieved. Determine whether the plasma electron temperature and its spatial distribution data obtained from the inversion are within the preset requirements. If they are not within the preset requirements, the plasma confinement state is identified as abnormal, and the corresponding electron temperature abnormality diagnosis result is output.

2. The diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator according to claim 1, characterized in that, The operating frequency band is U-band microwave.

3. The diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator according to claim 1, characterized in that, The first and second reflector groups are made of polytetrafluoroethylene.

4. The diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator according to claim 1, characterized in that, The focusing of the spontaneous microwave radiation signal from the plasma in the stellarator specifically includes: By scanning the focal length used for focusing using a preset formula, the correspondence between the emission distance and the focal length is obtained. Based on this correspondence, the focal length parameters of the Gaussian beam focusing position are matched and set so that the Gaussian beam is focused on the plasma core. The preset formula is: in, The launch distance; Focal length; The incident distance; Let be the Rayleigh length at the incident end.

5. The diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator according to claim 1, characterized in that, The receiving antenna of the electronics module is a polarized antenna.

6. A diagnostic method for measuring the electron temperature of a quasi-ring symmetric stellarator according to claim 5, characterized in that, The receiving antenna receives microwave radiation signals from the planar region of the stellarator, and the receiving antenna is at a preset distance from the plasma magnetic axis to avoid interference from the Doppler frequency shift effect on the measurement results.

7. A diagnostic system for measuring the electron temperature of a quasi-toroidal stellarator, based on the diagnostic method for measuring the electron temperature of a quasi-toroidal stellarator as described in claim 1, characterized in that, include: The quasi-optical module includes two sets of metal mirrors symmetrically distributed vertically. The two sets of metal mirrors are defined as the first mirror set and the second mirror set, respectively. The signal output terminals of the first mirror set and the second mirror set are connected to the electronics module through waveguides. The waveguide is provided with two input ports for receiving the first and second reflector groups respectively, and the output port of the waveguide is connected to the electronics module; the waveguide uses a U-band rectangular waveguide as the main transmission waveguide and is configured with a U-band linear transition waveguide as the waveguide transition section. The electronics module includes a radio frequency (RF) section and an intermediate frequency (IF) section. The RF section includes an antenna, a first filter, a second filter, a limiter, an RF isolator, a first mixer, a third filter, and a first amplifier connected in sequence. The first mixer is also connected to a voltage-controlled oscillator (VCO). The IF section includes a power divider, multiple parallel links, and an acquisition module connected in sequence. Each parallel link includes a fourth filter, a second amplifier, a second mixer, a variable attenuator, a fifth filter, a detector, a sixth filter, and a third amplifier. The second mixer is also connected to a local oscillator, and the output of the third amplifier is connected to the acquisition module. A blackbody source is positioned directly opposite the second set of mirrors, and the signal emitted by the blackbody source is input to the waveguide through the second set of mirrors.

8. A diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator according to claim 7, characterized in that, The waveguide is equipped with a mode groove waveguide adapted to the electron cyclotron radiation frequency.

9. A diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator according to claim 7, characterized in that, The effective receiving diameter of the metal mirror group of the quasi-optical module is set to be 3 times the width of the waist of the Gaussian beam in the plasma core.

10. A diagnostic system for measuring the electronic temperature of a quasi-ring symmetric stellarator according to claim 7, characterized in that, The electronics module adopts a heterodyne receiver and has a reserved expansion interface for a superheterodyne receiver.

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