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Su P, Zhong H, Tan Y, Gao Z, Zai Y, Liu H, Zeng L, Zhu X, Ling B, Cheng Z, Liu W, Wang S, Wang B. Implementation and data processing of a five-channel microwave interferometer with high temporal resolution and low noise on Sino-UNIted Spherical Tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:043538. [PMID: 34243439 DOI: 10.1063/5.0043667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/18/2021] [Indexed: 06/13/2023]
Abstract
A five-channel microwave interferometer with high temporal resolution and high phase resolution has been developed for measuring electron density profiles and fluctuations on the Sino-UNIted Spherical Tokamak. A correction algorithm, based on the low signal amplitude detection, is proposed to eliminate the fringe jump errors. The correction algorithm achieves an accuracy of 92%. The density profile is reconstructed through the Park-matrix method, with the geometry of magnetic surfaces calculated by the equilibrium fitting. The reconstructed density profiles for discharges with supersonic molecular beam injection are in good agreement with the results of another 94 GHz single-channel horizontal interferometer and the Langmuir probes. The temporal resolution of the system is 0.5 µs and the line-integrated electron density resolution is 1 × 1015 m-2, which benefits from the single sideband modulation technique. Therefore, the multichannel interferometer system is capable of studying the details of the high-frequency (up to 200 kHz) density fluctuation such as that in the minor disruption event.
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Affiliation(s)
- Pengjuan Su
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Heng Zhong
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yi Tan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhe Gao
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yingqi Zai
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Haiqing Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Long Zeng
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Xiang Zhu
- Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Bili Ling
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Zhengbo Cheng
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Wenbin Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Shouzhi Wang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Binbin Wang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China
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Chen Z, Li F, Zhuang G, Jian X, Zhu L. The rectangular array of magnetic probes on J-TEXT tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11D408. [PMID: 27910366 DOI: 10.1063/1.4959570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The rectangular array of magnetic probes system was newly designed and installed in the torus on J-TEXT tokamak to measure the local magnetic fields outside the last closed flux surface at a single toroidal angle. In the implementation, the experimental results agree well with the theoretical results based on the Spool model and three-dimensional numerical finite element model when the vertical field was applied. Furthermore, the measurements were successfully used as the input of EFIT code to conduct the plasma equilibrium reconstruction. The calculated Faraday rotation angle using the EFIT output is in agreement with the measured one from the three-wave polarimeter-interferometer system.
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Affiliation(s)
- Zhipeng Chen
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Fuming Li
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ge Zhuang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiang Jian
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lizhi Zhu
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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Chen W, Zhuang G, Gao L, Gentle KW, Chen J, Shi P, Liu Y, Li Q, Wang ZJ. Density modulation experiment to determine transport coefficients on Joint-TEXT Tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:023507. [PMID: 25725842 DOI: 10.1063/1.4906075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Density modulation experiments have been conducted on Joint-TEXT (J-TEXT) Tokamak Ohmic discharge to investigate particle transport based on a model with constant diffusion plus inward convection. Like the HCN interferometer, the newly developed three-wave polarimeter-interferometer system (POLARIS) is used to measure the perturbed density. The comparison of results between the HCN interferometer and POLARIS is given. The consistent results indicate the validity of the analysis scheme. At lower densities, the typical particle confinement time τp is found to increase with electron density, while it saturates at higher densities.
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Affiliation(s)
- W Chen
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - G Zhuang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - L Gao
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - K W Gentle
- Institute of Fusion Studies, University of Texas at Austin, Austin, Texas 78712, USA
| | - J Chen
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - P Shi
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Y Liu
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Q Li
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Z J Wang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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Liu HQ, Jie YX, Ding WX, Brower DL, Zou ZY, Li WM, Wang ZX, Qian JP, Yang Y, Zeng L, Lan T, Wei XC, Li GS, Hu LQ, Wan BN. Faraday-effect polarimeter-interferometer system for current density measurement on EAST. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D405. [PMID: 25430168 DOI: 10.1063/1.4889777] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10(16) m(-2) (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.
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Affiliation(s)
- H Q Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Y X Jie
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - W X Ding
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - D L Brower
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Z Y Zou
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - W M Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Z X Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - J P Qian
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Y Yang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - L Zeng
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - T Lan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - X C Wei
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - G S Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - B N Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
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Chen J, Zhuang G, Li Q, Liu Y, Gao L, Zhou YN, Jian X, Xiong CY, Wang ZJ, Brower DL, Ding WX. High resolution polarimeter-interferometer system for fast equilibrium dynamics and MHD instability studies on Joint-TEXT tokamak (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D303. [PMID: 25430163 DOI: 10.1063/1.4891603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A high-performance Faraday-effect polarimeter-interferometer system has been developed for the J-TEXT tokamak. This system has time response up to 1 μs, phase resolution < 0.1° and minimum spatial resolution ∼15 mm. High resolution permits investigation of fast equilibrium dynamics as well as magnetic and density perturbations associated with intrinsic Magneto-Hydro-Dynamic (MHD) instabilities and external coil-induced Resonant Magnetic Perturbations (RMP). The 3-wave technique, in which the line-integrated Faraday angle and electron density are measured simultaneously by three laser beams with specific polarizations and frequency offsets, is used. In order to achieve optimum resolution, three frequency-stabilized HCOOH lasers (694 GHz, >35 mW per cavity) and sensitive Planar Schottky Diode mixers are used, providing stable intermediate-frequency signals (0.5-3 MHz) with S/N > 50. The collinear R- and L-wave probe beams, which propagate through the plasma poloidal cross section (a = 0.25-0.27 m) vertically, are expanded using parabolic mirrors to cover the entire plasma column. Sources of systematic errors, e.g., stemming from mechanical vibration, beam non-collinearity, and beam polarization distortion are individually examined and minimized to ensure measurement accuracy. Simultaneous density and Faraday measurements have been successfully achieved for 14 chords. Based on measurements, temporal evolution of safety factor profile, current density profile, and electron density profile are resolved. Core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Effects of non-axisymmetric 3D RMP in ohmically heated plasmas are directly observed by polarimetry for the first time.
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Affiliation(s)
- J Chen
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - G Zhuang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Q Li
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Y Liu
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - L Gao
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Y N Zhou
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - X Jian
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - C Y Xiong
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Z J Wang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - D L Brower
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - W X Ding
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
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Zheng W, Liu R, Zhang M, Zhuang G, Yuan T. Design of FPGA based high-speed data acquisition and real-time data processing system on J-TEXT tokamak. FUSION ENGINEERING AND DESIGN 2014. [DOI: 10.1016/j.fusengdes.2014.01.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Li Q, Chen J, Zhuang G, Wang ZJ, Gao L, Chen W. Vibration mitigation in J-TEXT far-infrared diagnostic systems. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E314. [PMID: 23126974 DOI: 10.1063/1.4732071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.
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Affiliation(s)
- Q Li
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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