Interference fringe calibration system and method for doppler coherent imaging spectroscopy diagnostics

Abstract

The application discloses an interference fringe calibration system and method for Doppler coherent imaging spectrum diagnosis, which comprises a positive and negative double optical path Doppler coherent imaging system and an external moving light source. The positive and negative double optical path Doppler coherent imaging system respectively performs interference fringe imaging on the light with a target multiplet spectrum line in a same light-emitting area inside a magnetic confinement plasma device from two opposite directions. The moving external light source can realize switching between a device internal particle light-emitting measurement mode and an external laser measurement mode. In combination with the interference fringe image of the target multiplet spectrum line of the light-emitting area inside the device and the interference fringe image of the external laser, the actual center wavelength of the target multiplet spectrum line can be calculated, and the phase distribution of the interference fringe when the light-emitting particles inside the device are in non-directional motion is obtained to realize calibration. The application can avoid the problem that the particle velocity measurement is inaccurate due to the inconsistency between the database calculation center wavelength and the actual center wavelength during the interference fringe calibration.

Description

Technical Field

[0001] The present invention relates to the technical field of interference fringe calibration for spectral diagnosis, and in particular to an interference fringe calibration system and method for Doppler coherent imaging spectral diagnosis of a magnetic confinement plasma device. Background Art

[0002] Nuclear fusion energy, with its outstanding advantages of abundant reserves, environmental friendliness, and inherent safety, holds promise for addressing future energy needs and environmental challenges. Magnetic confinement plasma devices, which utilize magnetic fields to confine plasma, are a key approach to achieving controlled nuclear fusion. These devices include tokamaks, stellarators, reverse-field pinches, and linear devices. These devices differ primarily in the method or configuration of the magnetic field used to confine the plasma. Numerous studies, both domestically and internationally, have demonstrated that the plasma velocity distribution significantly influences the confinement performance of magnetic confinement devices and the thermal load on the device walls.

[0003] Doppler coherence imaging is a spectral diagnostic technology used to measure the two-dimensional distribution of particle (including neutral particles and charged particles) flow velocity. It has been applied to plasma research in some tokamaks, stellarators and linear devices. It also has application prospects in the measurement of flow velocity in flames, auroras, plasma thrusters, and the Earth's atmosphere. The basic principle of Doppler coherence imaging spectral diagnosis is to use a bandpass filter to filter the visible light emitted by the particles themselves to obtain the light of the target spectrum line, and then use a static modulated polarization interferometer to encode the spectral information of the target spectrum line on the two-dimensional interference fringe image. When the luminous particle has a directional motion relative to the detector, the Doppler frequency shift phenomenon occurs, that is, the frequency / wavelength of the detected light changes. The directional motion speed v of the luminous particle relative to the detector D The relationship between the wavelength (λ and λ0) with and without directional motion is shown in formula (1). Where u is the propagation speed of light, and λ0 is also called the central wavelength. When the luminous particle has directional motion relative to the detector and the detected wavelength changes, the interference fringes of Doppler coherent imaging spectroscopy diagnosis will move (that is, the phase of the interference fringes changes), and the dependence between the phase difference and the wavelength difference is shown in formula (2). Where φ m and φ C are the phases of interference fringes with and without directional motion, is the group delay parameter of the Doppler coherent imaging spectroscopy diagnostic system. The dependence between phase difference and velocity can be deduced from formula (1) and formula (2), as shown in formula (3). By comparing the phase of the interference fringe image with and without directional motion, the flow velocity v of the luminous particle can be calculated from the phase difference of the interference fringe. DTherefore, it is very critical to obtain the phase distribution of interference fringes (hereinafter referred to as interference fringes calibration) when the luminescent particles are in non-directional motion (ie, under the condition of central wavelength λ0).

[0004] v D =u(λ0-λ) / λ (1)

[0005]

[0006] There are many kinds of particles (hydrogen, deuterium, helium, carbon, nitrogen, oxygen, etc.) emitting light in magnetic confinement plasma devices. Due to the fine atomic energy level structure, the atomic spectral lines emitted by a certain particle due to energy level transitions are often not single, but present multiple states. The wavelengths of these multiplet spectral lines are very close (can be as low as 0.1 nanometers, or even 0.01 nanometers). In order to cover the particle velocity measurement range in magnetic confinement plasma devices (on the order of 0 to hundreds of kilometers per second), the bandwidth of the bandpass filter for Doppler coherent imaging spectroscopy diagnosis is usually at the nanometer level, so it is difficult to filter out one of the multiplet spectral lines alone. Existing Doppler coherent imaging interference fringe calibration uses the average wavelength λ with the relative light intensity of each spectral line in the multiplet spectral line as the weight. cal =∑ i I relative,i λ i As the central wavelength of the multiplet spectrum line. i is the wavelength of the i-th spectral line, I relative,i Its relative light intensity.

[0007] However, the relative light intensity of the target multiplet spectral lines selected for Doppler coherent imaging spectroscopy diagnosis is currently calculated using the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST). This database only considers the energy level transition probability and the statistical weight of excited-state atoms of the atomic spectral lines of the same luminescent particles when calculating the relative light intensity, but the actual relative light intensity depends on the actual light source. For magnetically confined plasma devices, due to the presence of multiple particles and a large number of spectral lines, the relative light intensity of the multiplet spectral lines will be affected by adjacent spectral lines and background light. These lights that cannot be filtered within the filtering range of the filter will change the relative light intensity of the multiplet spectral lines. Therefore, the central wavelength will also change accordingly.

[0008] The existing interference fringe calibration for Doppler coherent imaging spectroscopy diagnosis of magnetically confined plasma devices uses a wavelength-tunable laser to directly obtain the interference fringe phase under the central wavelength conditions calculated by the ASD database, or uses a spectral lamp with characteristic spectral lines to obtain the interference fringe phase under wavelength conditions close to the calculated central wavelength, and then extrapolates the interference fringe phase to the interference fringe phase under the central wavelength conditions calculated by the ASD database based on the static modulated polarization interferometer model. It is noted that the above two calibration methods ultimately use the interference fringe phase distribution under the central wavelength conditions calculated by the ASD database as the calibration image. As mentioned above, in magnetically confined plasma devices, the influence of adjacent spectral lines and background light can cause the actual central wavelength to be inconsistent with the central wavelength calculated by the ASD database. Therefore, the existing interference fringe calibration method itself has the problem of inaccurate particle velocity measurement due to the inconsistency between the central wavelength calculated by the database and the actual central wavelength. Summary of the Invention

[0009] The present invention aims to address the shortcomings of existing interference fringe calibration for Doppler coherence imaging spectroscopy diagnosis in magnetic confinement plasma devices and to provide an interference fringe calibration system and method for Doppler coherence imaging spectroscopy diagnosis. This system and method can avoid the problem of inaccurate particle velocity measurement caused by the inconsistency between the central wavelength calculated in the database and the actual central wavelength during interference fringe calibration. The system has an ingenious design, high reliability, and strong practicality, meeting the requirements for Doppler coherence imaging spectroscopy diagnosis measurements in magnetic confinement plasma devices.

[0010] The present invention is achieved through the following technical solutions:

[0011] In a first aspect, the present invention provides an interference fringe calibration system for Doppler coherent imaging spectral diagnosis, comprising several groups of forward and reverse dual-path Doppler coherent imaging systems and an external mobile light source; each group of forward and reverse dual-path Doppler coherent imaging systems comprises two Doppler coherent imaging systems, for performing interference fringe imaging of light having a wavelength of a target multiplet spectrum line in the same luminous region within a magnetic confinement plasma device from two opposite directions; the external mobile light source can be moved into each Doppler coherent imaging system to perform interference fringe imaging of the external mobile light source.

[0012] As a preferred embodiment of the present invention, each Doppler coherent imaging system includes a first-stage convex lens, a transmission optical fiber array, a second-stage convex lens, a third-stage convex lens, a fourth-stage convex lens, a bandpass filter, a static modulation polarization interferometer, a fifth-stage convex lens and a detection camera arranged in sequence, and the external movable light source can be moved between the second-stage convex lens and the third-stage convex lens.

[0013] As a preferred embodiment of the present invention, the first-stage convex lenses of the two Doppler coherent imaging systems in the same group are symmetrically arranged on both sides of the luminous object surface in the magnetic confinement plasma device.

[0014] As a preferred solution of the present invention, the bandpass filter, static modulation polarization interferometer, fifth-order convex lens and detection camera are all arranged in a constant temperature and shock absorption box, and the constant temperature and shock absorption box is preferably a constant temperature and shock absorption electromagnetic shielding room.

[0015] As a preferred embodiment of the present invention, the image plane of the first-stage convex lens coincides with the object plane at the head end of the transmission optical fiber array, and the image plane at the tail end of the transmission optical fiber array is located in the focal plane of the second-stage convex lens. After forming parallel light, it is imaged by the third-stage convex lens. The image plane formed is located in the focal plane of the fourth-stage convex lens. After forming parallel light, it passes through a bandpass filter, a static modulation polarization interferometer and a fifth-stage convex lens to form an interference fringe image, which is then photographed by a detection camera.

[0016] As a preferred solution of the present invention, the external movable light source includes a wavelength tunable laser and an integrating sphere. The integrating sphere can be moved between the second-stage convex lens and the third-stage convex lens. The laser output by the wavelength tunable laser enters the integrating sphere to form an extended light source and enters the third-stage convex lens.

[0017] As a preferred embodiment of the present invention, the external mobile light source further includes a splitter fiber bundle and a wavelength meter. The splitter fiber bundle is connected to the wavelength tunable laser to split the laser output by the wavelength tunable laser into two beams, one of which enters the integrating sphere to form an extended light source, and the other enters the wavelength meter to measure the laser wavelength.

[0018] As a preferred solution of the present invention, the integrating sphere is mounted on a displacement platform, and the displacement platform can drive the integrating sphere to move between the second-stage convex lens and the third-stage convex lens in each Doppler coherent imaging system.

[0019] In a second aspect, the present invention provides an interference fringe calibration method for Doppler coherent imaging spectroscopy diagnosis, utilizing the interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis described in the first aspect, comprising:

[0020] Move the external mobile light source to the first Doppler coherent imaging system of the same group. Set the wavelength of the external mobile light source to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. Obtain the interference fringe image CA, demodulate it, and obtain the initial calibration phase φ CA , the initial calibration phase at the center of the image is recorded as φ CA,0 ;

[0021] The external mobile light source is moved to the second Doppler coherent imaging system in the same group. The wavelength of the external mobile light source is set to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. The interference fringe image CB is obtained and demodulated to obtain the initial calibration phase φ. CB , the initial calibration phase at the center of the image is recorded as φ CB,0 ;

[0022] Remove the external mobile light source, and use the two Doppler coherent imaging systems of the same group to perform interference fringe imaging of the light with the wavelength of the target multiplet spectrum line in the same luminous area inside the magnetic confinement plasma device from two opposite directions. The first and second Doppler coherent imaging systems of the same group obtain the interference fringe images MA and MB respectively, and demodulate them respectively to obtain the measured phase φ MA and φ MB , the measured phase at the center of the image is recorded as φ MA,0 and φ MB,0 ;

[0023] According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the measured phase φ at the center of the image is MA,0 Relative to the initial calibration phase φ CA,0 The change of , the initial flow rate v of the luminescent particles is obtained DA,0 , given by the measured phase φ at the center of the image MB,0 Relative to the initial calibration phase φ CB,0 The change of , the initial flow rate v of the luminescent particles is obtained DB,0 ;

[0024] For the initial flow velocity v DA,0 and v DB,0 After correction, the speeds after correction are v ′ DA,0 =v DA,0 -(v DA,0 +v DB,0 ) / 2 and v ′ DB,0 =v DB,0 -(v DA,0 +v DB,0 ) / 2; According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the corrected velocity v ′ DA,0 and the measured phase φ MA,0 , inversely deduce the corrected calibration phase φ ′ CA,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle, the initial calibration phase φ CA,0 , the corrected calibration phase φ′ CA,0 and the calculated central wavelength of the target multiplet spectral line given by the ASD atomic spectrum database, the actual central wavelength of the target multiplet spectral line is obtained; or, according to the dependence between the phase difference and the velocity in the Doppler coherence imaging spectrum diagnosis principle, the corrected velocity v ′ DB,0 and the measured phase φ MB,0 , inversely deduce the corrected calibration phase φ ′ CB,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle, the initial calibration phase φ CB,0 , the corrected calibration phase φ ′ CB,0 and the calculated central wavelength of the target multiplet spectral line given by the ASD atomic spectrum database to obtain the actual central wavelength of the target multiplet spectral line;

[0025] Move the external mobile light source to the first Doppler coherent imaging system of the same group, set the wavelength of the external mobile light source to the actual central wavelength of the target multiplet spectrum line, obtain the interference fringe image CA, demodulate it, and obtain the actual calibration phase φ CA ′, that is, the phase distribution of interference fringes when the luminous particles in the magnetic confinement plasma device move without direction, to complete the calibration of the interference fringes; or, move the external mobile light source to the second Doppler coherent imaging system in the same group, set the wavelength of the external mobile light source to the actual central wavelength of the target multiplet spectrum line, obtain the interference fringe image CB, demodulate it, and obtain the actual calibration phase φ CB ′, that is, the phase distribution of the interference fringes when the luminous particles inside the magnetic confinement plasma device move in an undirected manner, completes the calibration of the interference fringes.

[0026] As a preferred solution of the present invention, according to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the measured phase φ MA Relative to the actual calibration phase φ CA ′, the two-dimensional distribution v of the luminous particle velocity measured by the first Doppler coherent imaging system of the same group can be obtained. ′ DA ; or, by measuring the phase φ MB Relative to the actual calibration phase φ CB ′, the two-dimensional distribution v of the luminous particle velocity measured by the second Doppler coherent imaging system of the same group can be obtained. ′ DB .

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] The present invention adopts a forward and reverse dual-path Doppler coherence imaging method to perform interference fringe imaging on light with a wavelength of a target multiplet spectrum line in the same luminescent area inside a magnetic confinement plasma device from two opposite directions. An external laser light source is moved to switch between a luminescence measurement mode of particles inside the magnetic confinement plasma device and an external laser measurement mode. The interference fringe image of the target multiplet spectrum line in the luminescent area inside the magnetic confinement plasma device and the interference fringe image of the external laser are then combined to calculate the actual center wavelength of the target multiplet spectrum line, ultimately obtaining the phase distribution of the interference fringes when the luminescent particles inside the magnetic confinement plasma device are in undirected motion, thereby achieving interference fringe calibration. The problem of inaccurate particle velocity measurement caused by the inconsistency between the calculated center wavelength in the database and the actual center wavelength during interference fringe calibration can be avoided. The design is ingenious, reliable, and practical, and meets the requirements for Doppler coherence imaging spectral diagnostic measurement of magnetic confinement plasma devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0030] Figure 1 This is a design diagram of the interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis in the present invention;

[0031] Figure 2 Schematic diagram of the state of the calibration system of the present invention when it is in the particle luminescence measurement mode inside the device;

[0032] Figure 3 Schematic diagram of the state of the calibration system of the present invention when it is in device external laser measurement mode I;

[0033] Figure 4 This is a schematic diagram of the state of the calibration system of the present invention when it is in the device external laser measurement mode II.

[0034] Markings and corresponding parts names in the accompanying drawings:

[0035] 1- luminous object surface in the magnetic confinement plasma device, 2- first-stage convex lens, 3- image plane 1A, 4- image plane 1B, 5- transmission fiber array, 6- image plane 2A, 7- image plane 2B, 8- second-stage convex lens, 9- third-stage convex lens, 10- image plane 3A, 11- image plane 3B, 12- fourth-stage convex lens, 13- bandpass filter, 14- static modulation polarization interferometer, 15- fifth-stage convex lens, 16- interference fringe image A, 17- interference fringe image B, 18- detection camera, 19- constant temperature and vibration reduction electromagnetic shielding room, 20- wavelength tunable laser, 21- spectrometer fiber bundle, 22- wavelength meter, 23- integrating sphere, 24- displacement platform;

[0036] 25 - Interference fringe image MA in the device internal particle luminescence measurement mode, 26 - Interference fringe image MB in the device internal particle luminescence measurement mode, 27 - Interference fringe image CA in the device external laser measurement mode I, 28 - Interference fringe image CB in the device external laser measurement mode II. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0039] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0040] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0042] In the embodiments of the present application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0043] For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0044] The interference fringe calibration of the existing magnetic confinement plasma device Doppler coherence imaging spectrum diagnosis uses the average wavelength λ with the relative intensity of each spectral line in the multiplet spectral line as the weight cal =∑ i I relative,i λ i As the central wavelength of the multiplet spectrum line. i is the wavelength of the i-th spectral line, I relative,i Its relative light intensity.

[0045] At present, the relative intensity of the target multiplet spectral lines selected for Doppler coherent imaging spectroscopy diagnosis is calculated using the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST). When calculating the relative intensity, this database only considers the energy level transition probability and the statistical weight of excited-state atoms of the atomic spectral lines of the same type of luminescent particles, but the actual relative intensity also depends on the actual light source. For magnetically confined plasma devices, due to the presence of multiple particles and a large number of spectral lines, the relative intensity of the multiplet spectral lines will be affected by adjacent spectral lines and background light. These lights that cannot be filtered within the filtering range of the filter will change the relative intensity of the multiplet spectral lines. Therefore, the central wavelength will also change accordingly.

[0046] The carbon ion (C 2+ ) as an example, in the range of 464-466 nm, the vacuum wavelength λ of the CIII triplet state spectrum is i The relative intensities of the CIII triplet state lines are 464.8720 nm, 465.1548 nm, and 465.2775 nm, respectively. relative,iare 0.5556, 0.3336, and 0.1108 respectively. According to the above, the central wavelength calculated by taking the relative intensity of each spectral line in the multiplet spectral line as the weight is λ cal Equal to 465.0113 nanometers. The following two situations will cause the central wavelength λ calculated by the database to be cal There is a deviation from the actual central wavelength λ0:

[0047] (1) Due to the existence of spectral broadening, if the adjacent spectral lines of the CIII triplet line (such as the oxygen ion OII line with wavelengths of 465.0437 nm and 465.2141 nm) cause a 5% increase in the intensity of the CIII 465.1548 nm line, the relative intensity of the CIII triplet line I relative,i will become 0.5291, 0.3653, 0.1055, so that the actual center wavelength becomes 465.0181 nanometers. The actual center wavelength differs from the center wavelength calculated by the database by 0.0068 nanometers. According to the Doppler frequency shift, that is, formula (1) in the background technology, the interference fringe calibration is performed using the center wavelength of the database, which will introduce an equivalent velocity deviation error u(λ0-λ cal ) / λ cal ≈4.4 km / s. For a Doppler coherent imaging spectroscopy diagnostic system with a group delay parameter of 1500, a phase change of π (-π) can measure a directional velocity of 100 km / s (-100 km / s), and the phase deviation introduced by the central wavelength deviation is ~8°;

[0048] (2) If there is a background light of 3% intensity, the relative intensity of the CIII triplet line I relative,i The actual center wavelength becomes 0.5372, 0.3336, and 0.1292, and the actual center wavelength becomes 465.0187 nanometers. The actual center wavelength differs from the center wavelength calculated by the database by 0.0074 nanometers. According to the Doppler frequency shift, that is, formula (1) in the background technology, the center wavelength calculated by the database is used for interference fringe calibration, which will introduce an equivalent velocity deviation error u(λ0-λ cal ) / λ cal For a Doppler coherent imaging spectroscopy diagnostic system (with a group delay parameter of 1500) that can measure a directional velocity of 100 km / s (-100 km / s) with a phase change of π (-π), the phase deviation introduced by the central wavelength deviation is ~9°.

[0049] To address the shortcomings of existing interference fringe calibration for Doppler coherent imaging spectroscopy diagnosis in magnetic confinement plasma devices, namely the problem of inaccurate particle velocity measurements due to the inconsistency between the central wavelength calculated in the database and the actual central wavelength, the inventors, after in-depth research, proposed an interference fringe calibration system and method for Doppler coherent imaging spectroscopy diagnosis. By adopting a forward and reverse dual-path Doppler coherent imaging system and an external mobile light source, combined with the interference fringe image of the target multiplet spectral line in the luminous region inside the magnetic confinement plasma device and the interference fringe image of the external laser, the actual central wavelength of the target multiplet spectral line can be calculated, and the phase distribution of the interference fringes when the luminous particles inside the magnetic confinement plasma device are in undirected motion can be obtained, thereby achieving interference fringe calibration.

[0050] Example 1

[0051] Please refer to Figure 1 An interference fringe calibration system for Doppler coherence imaging spectroscopy diagnosis provided in an embodiment of the present application includes several sets of forward and reverse dual-path Doppler coherence imaging systems and an external mobile light source; each set of forward and reverse dual-path Doppler coherence imaging systems includes two Doppler coherence imaging systems, which are used to perform interference fringe imaging of light with a wavelength of a target multiplet spectrum line in the same luminous area inside a magnetic confinement plasma device from two opposite directions; the external mobile light source can be moved to each Doppler coherence imaging system to perform interference fringe imaging of the external mobile light source.

[0052] It should be noted that, in this embodiment, only one group of forward and reverse dual-path Doppler coherent imaging systems, in which two Doppler coherent imaging systems are used as an example for explanation. Of course, multiple groups of forward and reverse dual-path Doppler coherent imaging systems can also be used, such as two groups, three groups, four groups, etc. However, as the number of Doppler coherent imaging systems increases, the overall cost will also increase. Therefore, using two Doppler coherent imaging systems is the most economical solution to achieve the interference fringe calibration.

[0053] The interference fringe calibration system in this embodiment uses forward and reverse dual-path Doppler coherence imaging to perform interference fringe imaging of light with a target multiplet wavelength in the same luminescent region within a magnetic confinement plasma device from two opposite directions. By moving an external mobile light source, the system can switch between a luminescence measurement mode for particles within the magnetic confinement plasma device and an external mobile light source measurement mode. Combining the interference fringe images of the target multiplet wavelength in the luminescent region within the magnetic confinement plasma device with the interference fringe images of the external mobile light source, the actual center wavelength of the target multiplet wavelength can be calculated. Ultimately, the phase distribution of the interference fringes during the undirected motion of luminescent particles within the magnetic confinement plasma device is obtained, thereby achieving interference fringe calibration. This interference fringe calibration system avoids the problem of inaccurate particle velocity measurements caused by inconsistencies between the calculated center wavelength in the database and the actual center wavelength during interference fringe calibration. The system features an ingenious design, high reliability, and strong practicality, meeting the requirements for Doppler coherence imaging spectral diagnostic measurements of magnetic confinement plasma devices.

[0054] According to some embodiments of the present application, each Doppler coherent imaging system includes a first-stage convex lens 2, a transmission fiber array 5, a second-stage convex lens 8, a third-stage convex lens 9, a fourth-stage convex lens 12, a bandpass filter 13, a statically modulated polarization interferometer 14, a fifth-stage convex lens 15, and a detection camera 18, which are arranged in sequence. The external movable light source can be moved between the second-stage convex lens 8 and the third-stage convex lens 9. Because each Doppler coherent imaging system represents an independent imaging optical path, two Doppler coherent imaging systems can be used to perform interference fringe imaging of light with a wavelength of a target multiplet spectrum line from the same luminous region within a magnetic confinement plasma device from two opposite directions. Furthermore, because the external movable light source can be moved between the second-stage convex lens 8 and the third-stage convex lens 9, it can block light emitted by particles within the magnetic confinement plasma device and output light to the third-stage convex lens 9, thereby switching the measurement light source from the luminous object surface 1 within the magnetic confinement plasma device to the external movable light source, thereby achieving interference fringe imaging of the external movable light source.

[0055] According to some embodiments of the present application, the first-stage convex lenses 2 of two Doppler coherence imaging systems in the same group are symmetrically arranged on either side of the luminous object surface 1 within the magnetic confinement plasma device. By adopting this design, interference fringe imaging is performed from two opposite directions on light with a wavelength of the target multiplet spectrum line in the same luminous region within the magnetic confinement plasma device. The Doppler effect-based flow velocities of the luminous particles at the center of the images obtained by the two optical paths are equal and opposite in direction, facilitating subsequent correction of the initial flow velocity.

[0056] According to some embodiments of the present application, the bandpass filter 13, the statically modulated polarization interferometer 14, the fifth-stage convex lens 15, and the detection camera 18 are all disposed in a constant temperature and shock-absorbing box, which is preferably a constant temperature and shock-absorbing electromagnetic shielding room 19. By installing the bandpass filter 13, the statically modulated polarization interferometer 14, the fifth-stage convex lens 15, and the detection camera 18 in a constant temperature and shock-absorbing electromagnetic shielding room 19, the effects of vibration displacement and temperature changes on the statically modulated polarization interferometer 14 and the interference fringe image can be avoided, and interference of the electromagnetic field on the detection camera 18 can be prevented.

[0057] It should be noted that the bandpass filter 13, statically modulated polarization interferometer 14, fifth-stage convex lens 15 and detection camera 18 in the two Doppler coherent imaging systems can be set together in a constant temperature and shock-absorbing electromagnetic shielding room 19, and of course they can also be set separately in two constant temperature and shock-absorbing electromagnetic shielding rooms.

[0058] According to some embodiments of the present application, the image plane of the first-stage convex lens 2 coincides with the object plane at the head end of the transmission fiber array 5, and the image plane at the tail end of the transmission fiber array 5 is located in the focal plane of the second-stage convex lens 8. After forming parallel light, it is imaged by the third-stage convex lens 9. The image plane formed is located in the focal plane of the fourth-stage convex lens 12. After forming parallel light, it passes through the bandpass filter 13, the static modulation polarization interferometer 14 and the fifth-stage convex lens 15 to form an interference fringe image, which is then photographed by the detection camera 18. By using the transmission fiber array 5 to spatially transmit the image plane of the first-stage convex lens 2, the advantage is that the entire optical path does not have to be in a straight line, which is more flexible in space. In addition, optical fiber transmission allows the subsequent optical path and optical devices (mainly the detection camera 18) to be arranged at a long distance to avoid them being interfered with by the electromagnetic field of the magnetic confinement plasma device.

[0059] According to some embodiments of the present application, the external movable light source includes a wavelength tunable laser 20 and an integrating sphere 23. The integrating sphere 23 can be moved between the second-stage convex lens 8 and the third-stage convex lens 9. The laser output by the wavelength tunable laser 20 enters the integrating sphere 23 to form an extended light source and enters the third-stage convex lens 9.

[0060] According to some embodiments of the present application, the external mobile light source further includes a splitter fiber bundle 21 and a wavelength meter 22. The splitter fiber bundle 21 is connected to the wavelength tunable laser 20 to split the laser output by the wavelength tunable laser 20 into two beams, one of which enters the integrating sphere 23 to form an extended light source, and the other enters the wavelength meter 22 to measure the laser wavelength. The laser wavelength can be adjusted according to the wavelength result measured by the wavelength meter 22.

[0061] According to some embodiments of the present application, the integrating sphere 23 is mounted on a displacement platform 24, which can drive the integrating sphere 23 to move between the second-stage convex lens 8 and the third-stage convex lens 9 in two Doppler coherent imaging systems. By mounting the integrating sphere 23 on the displacement platform 24, a position adjustment function is provided. When the integrating sphere 23 moves between the second-stage convex lens 8 and the third-stage convex lens 9 in either Doppler coherent imaging system, the measurement light source can be switched from the luminous object plane 1 in the magnetic confinement plasma device to an external laser.

[0062] Specifically, the interference fringe calibration system adopts a forward and reverse dual-path Doppler coherence imaging method. When the magnetic confinement plasma device is discharging, two first-stage convex lenses 2 are symmetrically arranged about the luminous object surface 1 in the magnetic confinement plasma device to image the same luminous object surface from two opposite directions, forming image plane 1A3 and image plane 1B4. The images are then transmitted through two transmission optical fiber arrays 5 respectively. The image planes 2A6 and 2B7 at the tail ends of the transmission optical fiber arrays 5 are respectively located in the focal planes of the two second-stage convex lenses 8. After forming parallel light, the two third-stage convex lenses 9 are used to image the image planes 3A10 and 3B11 formed. The image planes 3A10 and 3B11 are respectively located in the focal planes of the two fourth-stage convex lenses 12. After forming parallel light, the two third-stage convex lenses 9 pass through the bandpass filter 13, the static modulation polarization interferometer 14 and the fifth-stage convex lens 15 respectively to form interference fringe images A16 and B17 of the target multiplet spectrum line, which are then photographed by two detection cameras 18. The bandpass filter 13, statically modulated polarization interferometer 14, fifth-stage convex lens 15, and detection camera 18 are installed in a constant-temperature, vibration-damping electromagnetic shielding chamber 19 to protect the statically modulated polarization interferometer 14 from vibration, displacement, and temperature changes, and to prevent electromagnetic interference with the detection camera 18. By moving the integrating sphere 23, mounted on a displacement platform 24, to a position between the second-stage convex lens 8 and the third-stage convex lens 9, the measurement light source can be switched from the luminous object plane 1 within the magnetic confinement plasma device to the extended light source of the wavelength-tunable laser 20. The light output by the wavelength tunable laser 20 is divided into two beams by using a splitting fiber bundle 21. One beam enters the wavelength meter 22 to measure the laser wavelength. According to the measurement result of the wavelength meter 22, the wavelength of the wavelength tunable laser 20 can be adjusted. The other beam enters the integrating sphere 23 to form an extended light source, and then passes through the third-stage convex lens 9, the fourth-stage convex lens 12, the bandpass filter 13, the static modulation polarization interferometer 14 and the fifth-stage convex lens 15 to form interference fringe images A16 and B17 of the external laser, which are then photographed by two detection cameras 18.

[0063] Example 2

[0064] Please refer to Figures 2 to 4The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis in this application has three working modes, namely, the particle luminescence measurement mode inside the magnetic confinement plasma device (see Figure 2 ), external laser measurement mode I of magnetic confinement plasma device (see Figure 3 ) and external laser measurement mode II of magnetic confinement plasma device (see Figure 4 By combining the three working modes, the phase distribution of interference fringes when luminous particles in a magnetically confined plasma device move in an undirected manner (i.e., at the actual central wavelength of the target multiplet spectrum) can be obtained, thus achieving interference fringes calibration.

[0065] An interference fringe calibration method for Doppler coherent imaging spectroscopy diagnosis provided in the embodiments of the present application uses the interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis described in Example 1, comprising:

[0066] Using the external laser measurement mode I of the magnetic confinement plasma device, the integrating sphere 23 is moved to the position of the integrating sphere 23 under the external laser measurement mode I of the magnetic confinement plasma device (such as Figure 3 The wavelength of the wavelength-tunable laser 20 is set to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. The interference fringe image CA 27 in the external laser measurement mode I of the magnetic confinement plasma device is captured and demodulated to obtain the initial calibration phase φ CA , the initial calibration phase at the center of the image is recorded as φ CA,0 .

[0067] Using the external laser measurement mode II of the magnetic confinement plasma device, the integrating sphere 23 is moved to the position of the integrating sphere 23 under the external laser measurement mode II of the magnetic confinement plasma device (such as Figure 4 The wavelength of the wavelength-tunable laser 20 is set to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. The interference fringe image CB 28 in the external laser measurement mode II of the magnetic confinement plasma device is captured and demodulated to obtain the initial calibration phase φ CB , the initial calibration phase at the center of the image is recorded as φ CB,0 .

[0068] The magnetic confinement plasma device internal particle luminescence measurement mode is adopted, and the integrating sphere 23 is moved to the position of the integrating sphere 23 in the magnetic confinement plasma device internal particle luminescence measurement mode (such as Figure 2 ), capture the interference fringe image MA 25 and the interference fringe image MB 26 in the magnetic confinement plasma device internal particle luminescence measurement mode, demodulate them respectively, and obtain the measurement phase φMA and φ MB , the measured phase at the center of the image is recorded as φ MA,0 and φ MB,0 .

[0069] According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle (i.e., formula (3) in the background technology), the measured phase φ at the center of the image is MA,0 Relative to the initial calibration phase φ CA,0 The change of , the initial flow rate v of the luminescent particles is obtained DA,0 , given by the measured phase φ at the center of the image MB,0 Relative to the initial calibration phase φ CB,0 The change of , the initial flow rate v of the luminescent particles is obtained D8,0 .

[0070] According to the design of the forward and reverse dual-path Doppler coherent imaging of the fringe calibration system, the interference fringe imaging of the light with the wavelength of the target multiplet spectrum line in the same luminous area inside the magnetic confinement plasma device is performed from two opposite directions. The flow velocities of the luminous particles at the center of the image obtained by the two light paths based on the Doppler effect are equal and opposite (that is, the sum is 0), so the initial flow velocity v DA,0 and v DB,0 Make corrections. The corrected speeds are v ′ DA,0 =v DA,0 -(v DA,0 +v DB,0 ) / 2 and v ′ DB,0 =v DB,0 -(v DA,0 +v DB,0 ) / 2. According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle (i.e., formula (3) in the background technology), the corrected velocity v ′ DA,0 and the measured phase φ MA,0 , inversely deduce the corrected calibration phase φ ′ CA,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle (i.e. formula (2) in the background technology), the initial calibration phase φ CA,0 , the corrected calibration phase φ ′ CA,0 The actual central wavelength of the target multiplet spectrum line is obtained by combining the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. Of course, the corrected velocity v can also be obtained based on the dependence between the phase difference and the velocity in the Doppler coherent imaging spectrum diagnosis principle (i.e., formula (3) in the background technology). ′DB,0 and the measured phase φ MB,0 , inversely deduce the corrected calibration phase φ ′ CB,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle (i.e. formula (2) in the background technology), the initial calibration phase φ CB,0 , the corrected calibration phase φ ′ CB,0 The actual central wavelength of the target multiplet spectral line is obtained by comparing the calculated central wavelength of the target multiplet spectral line given by the ASD atomic spectrum database.

[0071] Then, the external laser measurement mode I of the magnetic confinement plasma device is adopted, and the integrating sphere 23 is moved to the position of the integrating sphere 23 under the external laser measurement mode I of the magnetic confinement plasma device (such as Figure 3 ), set the wavelength of the wavelength tunable laser 20 to the actual central wavelength of the target multiplet spectrum line, capture the interference fringe image CA27 under the external laser measurement mode I of the magnetic confinement plasma device, demodulate it, and obtain the actual calibration phase φ CA ', that is, the phase distribution of the interference fringes when the luminous particles in the magnetic confinement plasma device move without direction, to complete the calibration of the interference fringes. Of course, the external laser measurement mode II of the magnetic confinement plasma device can also be used to move the integrating sphere 23 to the position of the integrating sphere 23 under the external laser measurement mode II of the magnetic confinement plasma device (such as Figure 4 The wavelength of the wavelength tunable laser 20 is set to the actual central wavelength of the target multiplet spectrum line, and the interference fringe image CB 28 is obtained and demodulated to obtain the actual calibration phase φ CB ′, that is, the phase distribution of the interference fringes when the luminous particles inside the magnetic confinement plasma device move in an undirected manner, completes the calibration of the interference fringes.

[0072] Subsequently, according to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle (i.e., formula (3) in the background technology), the measured phase φ MA Relative to the actual calibration phase φ CA ′, the two-dimensional distribution v of the luminous particle velocity measured by the first Doppler coherent imaging system of the same group can be obtained. ′ DA Of course, the phase φ can also be measured MB Relative to the actual calibration phase φ CB ′, the two-dimensional distribution v of the luminous particle velocity measured by the second Doppler coherent imaging system of the same group can be obtained. ′ DB .

[0073] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is 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 in the scope of protection of the present invention.

Claims

1. An interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis, characterized in that: The invention comprises several groups of forward and reverse dual-path Doppler coherent imaging systems and an external mobile light source; each group of forward and reverse dual-path Doppler coherent imaging systems comprises two Doppler coherent imaging systems, which are used to perform interference fringe imaging of light with a wavelength of a target multiplet spectrum line in the same luminous area inside a magnetic confinement plasma device from two opposite directions; the external mobile light source can be moved into each Doppler coherent imaging system to perform interference fringe imaging of the external mobile light source.

2. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 1, characterized in that: Each Doppler coherent imaging system includes a first-stage convex lens, a transmission fiber array, a second-stage convex lens, a third-stage convex lens, a fourth-stage convex lens, a bandpass filter, a static modulation polarization interferometer, a fifth-stage convex lens and a detection camera arranged in sequence, and the external mobile light source can be moved between the second-stage convex lens and the third-stage convex lens.

3. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 2, characterized in that: The first-stage convex lenses of two Doppler coherent imaging systems in the same group are symmetrically arranged on both sides of the luminous object surface in the magnetic confinement plasma device.

4. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 2, characterized in that: The bandpass filter, static modulation polarization interferometer, fifth-order convex lens and detection camera are all arranged in a constant temperature and shock absorption box, and the constant temperature and shock absorption box is preferably a constant temperature and shock absorption electromagnetic shielding room.

5. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 2, characterized in that: The image plane of the first-stage convex lens coincides with the object plane at the head end of the transmission optical fiber array, and the image plane at the tail end of the transmission optical fiber array is located in the focal plane of the second-stage convex lens. After forming parallel light, it is imaged through the third-stage convex lens. The image plane formed is located in the focal plane of the fourth-stage convex lens. After forming parallel light, it passes through a bandpass filter, a static modulation polarization interferometer and a fifth-stage convex lens to form an interference fringe image, which is then photographed by a detection camera.

6. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to any one of claims 2 to 5, characterized in that: The external movable light source includes a wavelength tunable laser and an integrating sphere. The integrating sphere can be moved between the second-stage convex lens and the third-stage convex lens. The laser output by the wavelength tunable laser enters the integrating sphere to form an extended light source and enters the third-stage convex lens.

7. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 6, characterized in that: The external mobile light source also includes a splitter fiber bundle and a wavelength meter. The splitter fiber bundle is connected to the wavelength tunable laser to split the laser output by the wavelength tunable laser into two beams, one of which enters the integrating sphere to form an extended light source, and the other enters the wavelength meter to measure the laser wavelength.

8. The interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to claim 6, characterized in that: The integrating sphere is mounted on a displacement platform, and the displacement platform can drive the integrating sphere to move between the second-stage convex lens and the third-stage convex lens in each Doppler coherent imaging system.

9. An interference fringe calibration method for Doppler coherent imaging spectroscopy diagnosis, utilizing the interference fringe calibration system for Doppler coherent imaging spectroscopy diagnosis according to any one of claims 1 to 8, characterized in that: include: Move the external mobile light source to the first Doppler coherent imaging system of the same group. Set the wavelength of the external mobile light source to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. Obtain the interference fringe image CA, demodulate it, and obtain the initial calibration phase φ CA , the initial calibration phase at the center of the image is recorded as φ CA,0 ; The external mobile light source is moved to the second Doppler coherent imaging system in the same group. The wavelength of the external mobile light source is set to the calculated central wavelength of the target multiplet spectrum line given by the ASD atomic spectrum database. The interference fringe image CB is obtained and demodulated to obtain the initial calibration phase φ. CB , the initial calibration phase at the center of the image is recorded as φ CB,0 ; Remove the external mobile light source, and use the two Doppler coherent imaging systems of the same group to perform interference fringe imaging of the light with the wavelength of the target multiplet spectrum line in the same luminous area inside the magnetic confinement plasma device from two opposite directions. The first and second Doppler coherent imaging systems of the same group obtain the interference fringe images MA and MB respectively, and demodulate them respectively to obtain the measured phase φ MA and φ MB , the measured phase at the center of the image is recorded as φ MA,0 and φ MB,0 ; According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the measured phase φ at the center of the image is MA,0 Relative to the initial calibration phase φ CA,0 The change of , the initial flow rate v of the luminescent particles is obtained DA,0 , given by the measured phase φ at the center of the image MB,0 Relative to the initial calibration phase φ CB,0 The change of , the initial flow rate v of the luminescent particles is obtained DB,0 ; For the initial flow velocity v DA,0 and v DB,0 After correction, the speeds after correction are v ′ DA,0 =v DA,0 -(v DA,0 +v DB,0 ) / 2 and v ′ DB,0 =v DB,0 -(v DA,0 +v DB,0 ) / 2; According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the corrected velocity v ′ DA,0 and the measured phase φ MA,0 , inversely deduce the corrected calibration phase φ ′ CA,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle, the initial calibration phase φ CA,0 , the corrected calibration phase φ ′ CA,0 and the calculated central wavelength of the target multiplet spectral line given by the ASD atomic spectrum database, the actual central wavelength of the target multiplet spectral line is obtained; or, according to the dependence between the phase difference and the velocity in the Doppler coherence imaging spectrum diagnosis principle, the corrected velocity v ′ DB,0 and the measured phase φ MB,0 , inversely deduce the corrected calibration phase φ ′ CB,0 According to the dependence between phase difference and wavelength difference in the Doppler coherence imaging spectrum diagnosis principle, the initial calibration phase φ CB,0 , the corrected calibration phase φ ′ CB,0 and the calculated central wavelength of the target multiplet spectral line given by the ASD atomic spectrum database to obtain the actual central wavelength of the target multiplet spectral line; Move the external mobile light source to the first Doppler coherent imaging system of the same group, set the wavelength of the external mobile light source to the actual central wavelength of the target multiplet spectrum line, obtain the interference fringe image CA, demodulate it, and obtain the actual calibration phase φ CA ′, that is, the phase distribution of interference fringes when the luminous particles in the magnetic confinement plasma device move without direction, to complete the calibration of the interference fringes; or, move the external mobile light source to the second Doppler coherent imaging system in the same group, set the wavelength of the external mobile light source to the actual central wavelength of the target multiplet spectrum line, obtain the interference fringe image CB, demodulate it, and obtain the actual calibration phase φ CB ′, that is, the phase distribution of the interference fringes when the luminous particles inside the magnetic confinement plasma device move in an undirected manner, completes the calibration of the interference fringes.

10. The interference fringe calibration method for Doppler coherent imaging spectroscopy diagnosis according to claim 9, characterized in that: According to the dependence between phase difference and velocity in the Doppler coherence imaging spectrum diagnosis principle, the measured phase φ MA Relative to the actual calibration phase φ CA ′, the two-dimensional distribution v of the luminous particle velocity measured by the first Doppler coherent imaging system of the same group can be obtained. ′ DA ; or, by measuring the phase φ MB Relative to the actual calibration phase φ CB ′, the two-dimensional distribution v of the luminous particle velocity measured by the second Doppler coherent imaging system of the same group can be obtained. ′ DB .

Images