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Zhou Y, Tong RH, Zhong WL, Tan Y, Jiang M, Shi ZB, Yang ZC, Shen YQ, Wen J, Liang AS. Quasi-optical design for the cross-polarization scattering diagnostic on the HL-3 tokamak. Rev Sci Instrum 2024; 95:053507. [PMID: 38758767 DOI: 10.1063/5.0211022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/29/2024] [Indexed: 05/19/2024]
Abstract
As the plasma beta (β) increases in high-performance tokamaks, electromagnetic turbulence becomes more significant, potentially constraining their operational range. To investigate this turbulence, a cross-polarization scattering (CPS) diagnostic system is being developed on the HL-3 tokamak for simultaneous measurements of density and magnetic fluctuations. In this work, a quasi-optical system has been designed and analyzed for the Q-band CPS diagnostic. The system includes a lens group for beam waist size optimization, a rotatable wire-grid polarizer for polarization adjustment, and a reflector group for measurement range regulation and system response enhancement. Laboratory tests demonstrated a beam radius of order 4 cm at the target measurement location (near the plasma pedestal), cross-polarization isolation exceeding 30 dB, and poloidal and toroidal angle adjustment ranges of ±40° and ±15°, respectively. These results verify the system's feasibility through laboratory evaluations. The quasi-optical system has been installed on the HL-3 tokamak during the 2023 experimental campaign to support the development of CPS diagnostics.
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Affiliation(s)
- Y Zhou
- Southwestern Institute of Physics, Chengdu 610041, China
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - R H Tong
- Southwestern Institute of Physics, Chengdu 610041, China
| | - W L Zhong
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Y Tan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - M Jiang
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Z B Shi
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Z C Yang
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Y Q Shen
- Southwestern Institute of Physics, Chengdu 610041, China
| | - J Wen
- Southwestern Institute of Physics, Chengdu 610041, China
| | - A S Liang
- Southwestern Institute of Physics, Chengdu 610041, China
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2
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Qiu S, Himes L, Domier C, Tang X, Liu X, Hu F, Yu G, Li X, Zhu Y, Luhmann N, Xie J, Wu Z. Design of a 140 GHz waveguide notch filter for millimeter-wave receiver module protection in fusion plasma diagnostics. Rev Sci Instrum 2024; 95:023503. [PMID: 38350476 DOI: 10.1063/5.0176796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 01/17/2024] [Indexed: 02/15/2024]
Abstract
A carefully designed waveguide-based millimeter-wave notch filter, operating at 140 GHz, safeguards plasma diagnostic instruments from gyrotron leakage. Utilizing cylindrical cavity resonators with aperture coupling, the filter efficiently resonates 140 GHz wave-power into the TE11p mode, optimizing various geometrical parameters for practical fabrication and high-yield production. Thorough thermal analysis ensures its ability to handle power. The filter achieves outstanding performance with over 90 dB rejection at 140 GHz while providing low insertion loss over the passband (110-138 GHz), which is ideally suited for system-on-chip approach F-band diagnostic system applications.
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Affiliation(s)
- Shasha Qiu
- University of California Davis, Davis, California 95616, USA
| | - Logan Himes
- University of California Davis, Davis, California 95616, USA
| | - Calvin Domier
- University of California Davis, Davis, California 95616, USA
| | - Xiaopin Tang
- University of California Davis, Davis, California 95616, USA
| | - Xianzi Liu
- University of California Davis, Davis, California 95616, USA
| | - Fengqi Hu
- University of California Davis, Davis, California 95616, USA
| | - Guanying Yu
- University of California Davis, Davis, California 95616, USA
| | - Xiaoliang Li
- University of California Davis, Davis, California 95616, USA
| | - Yilun Zhu
- University of California Davis, Davis, California 95616, USA
| | - Neville Luhmann
- University of California Davis, Davis, California 95616, USA
| | - Jinlin Xie
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhengwei Wu
- University of Science and Technology of China, Hefei, Anhui 230026, China
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3
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Hong R, Rhodes TL, Wang G, Peebles WA. Ray-tracing analysis for cross-polarization scattering diagnostic on MAST-upgrade spherical tokamak. Rev Sci Instrum 2021; 92:063505. [PMID: 34243511 DOI: 10.1063/5.0043600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
A combined Doppler backscattering/cross-polarization scattering (DBS/CPS) system is being deployed on MAST-U for simultaneous measurements of local density turbulence, turbulence flows, and magnetic turbulence. In this design, CPS shares the probing beam with the DBS and uses a separate parallel-viewing receiver system. In this study, we utilize a modified GENRAY 3D ray-tracing code to simulate the propagation of the probing and scattered beams. The contributions of different scattering locations along the entire beam trajectories are considered, and the corresponding local B̃ wavenumbers are estimated using the wavevector matching criterion. The wavenumber ranges of the local B̃ that are detectable to the CPS system are explored for simulated L- and H-mode plasmas.
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Affiliation(s)
- R Hong
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - T L Rhodes
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - G Wang
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - W A Peebles
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
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Zhu Y, Yu JH, Yu G, Ye Y, Chen Y, Tobias B, Diallo A, Kramer G, Ren Y, Tang W, Dong G, Churchill R, Domier CW, Li X, Luo C, Chen M, Luhmann NC. System-on-chip upgrade of millimeter-wave imaging diagnostics for fusion plasma. Rev Sci Instrum 2021; 92:053522. [PMID: 34243257 DOI: 10.1063/5.0040449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 04/23/2021] [Indexed: 06/13/2023]
Abstract
Monolithic, millimeter wave "system-on-chip" technology has been employed in chip heterodyne radiometers in a newly developed Electron Cyclotron Emission Imaging (ECEI) system on the DIII-D tokamak for 2D electron temperature and fluctuation diagnostics. The system employs 20 horn-waveguide receiver modules each with customized W-band (75-110 GHz) monolithic microwave integrated circuit chips comprising a W-band low noise amplifier, a balanced mixer, a ×2 local oscillator (LO) frequency doubler, and two intermediate frequency amplifier stages in each module. Compared to previous quasi-optical ECEI arrays with Schottky mixer diodes mounted on planar antennas, the upgraded W-band array exhibits >30 dB additional gain and 20× improvement in noise temperature; an internal eight times multiplier chain is used to provide LO coupling, thereby eliminating the need for quasi-optical coupling. The horn-waveguide shielding housing avoids out-of-band noise interference on each module. The upgraded ECEI system plays an important role for absolute electron temperature and fluctuation measurements for edge and core region transport physics studies. An F-band receiver chip (up to 140 GHz) is under development for additional fusion facilities with a higher toroidal magnetic field. Visualization diagnostics provide multi-scale and multi-dimensional data in plasma profile evolution. A significant aspect of imaging measurement is focusing on artificial intelligence for science applications.
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Affiliation(s)
- Y Zhu
- University of California Davis, Davis, California 95616, USA
| | - J-H Yu
- University of California Davis, Davis, California 95616, USA
| | - G Yu
- University of California Davis, Davis, California 95616, USA
| | - Y Ye
- University of California Davis, Davis, California 95616, USA
| | - Y Chen
- University of California Davis, Davis, California 95616, USA
| | - B Tobias
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A Diallo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - G Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - Y Ren
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - W Tang
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - G Dong
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Churchill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C W Domier
- University of California Davis, Davis, California 95616, USA
| | - X Li
- University of Science and Technology of China, Hefei, Anhui 230000, China
| | - C Luo
- University of California Davis, Davis, California 95616, USA
| | - M Chen
- University of California Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California Davis, Davis, California 95616, USA
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Ji JX, Liu AD, Zhou C, Zhuang G, Zhang J, Feng X, Liu ZY, Zhong XM, Fan HR, Zhang SB, Liu Y, Hu LQ, Mao WZ, Lan T, Xie JL, Li H, Liu ZX, Liu WD. The cross-polarization scattering system for the magnetic fluctuation measurement in the Experimental Advanced Superconducting Tokamak. Rev Sci Instrum 2021; 92:043511. [PMID: 34243396 DOI: 10.1063/5.0012520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 03/16/2021] [Indexed: 06/13/2023]
Abstract
The cross-polarization scattering (CPS) system for magnetic fluctuation measurements in the Experimental Advanced Superconducting Tokamak (EAST) has been designed and installed. Different from the Doppler reflectometer (DR) system, the CPS system detects the perpendicular polarization of the electromagnetic wave induced by magnetic fluctuations B̃. The CPS system in the EAST has been developed from the existing Doppler reflectometer system, and they are integrated together for simultaneous measurement of magnetic and density fluctuations. Ray-tracing simulations are used to calculate the scattering locations and the wavenumber coverage of the magnetic fluctuation for CPS. In the experiments, the CPS and DR system data were different in Doppler shift, amplitude, and spectrum broadening. In this article, the hardware design, the ray tracing, and the preliminary results of the system in the EAST are presented.
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Affiliation(s)
- J X Ji
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - A D Liu
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - C Zhou
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - G Zhuang
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - J Zhang
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - X Feng
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Z Y Liu
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - X M Zhong
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - H R Fan
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - S B Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Anhui, Hefei 230021, China
| | - Y Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Anhui, Hefei 230021, China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Anhui, Hefei 230021, China
| | - W Z Mao
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - T Lan
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - J L Xie
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - H Li
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Z X Liu
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - W D Liu
- School of Nuclear Sciences and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
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Chen J, Ding WX, Brower DL, Finkenthal D, Boivin R. A Faraday-effect polarimeter for fast magnetic dynamics measurement on DIII-D. Rev Sci Instrum 2018; 89:10B101. [PMID: 30399782 DOI: 10.1063/1.5035276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A Faraday-effect-based radial-interferometer-polarimeter diagnostic has been developed to explore fast magnetic dynamics in high-performance DIII-D plasmas. The instrument measures radial magnetic field perturbations using three chords positioned near the magnetic axis. Newly developed solid-state sources operating at 650 GHz provide phase noise down to 0.01°/ k H z and tunable bandwidth up to 10 MHz. Various systematic errors which can contaminate the polarimetric measurement have been investigated in detail. Distortion of circular polarization due to non-ideal optical components is calibrated using a rotating quarter wave plate technique. The impact of perpendicular magnetic field, i.e., the Cotton-Mouton effect, is evaluated. The error due to non-collinearity of probe beams is minimized to less than 0.5° for electron density up to 7 × 1019 m-3 by alignment optimization. Optical feedback, due to multiple reflections induced by the double-pass configuration, is identified and reduced. Coherent and broadband high-frequency magnetic fluctuations for DIII-D H-mode plasmas are observed.
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Affiliation(s)
- J Chen
- Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - W X Ding
- Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - D L Brower
- Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - D Finkenthal
- Palomar Scientific Instruments, San Marcos, California 92078, USA
| | - R Boivin
- General Atomics, San Diego, California 92121-1122, USA
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Wang G, Rhodes TL, Crocker NA, Peebles WA, Barada K. First step toward a synthetic diagnostic for magnetic fluctuation measurements using cross-polarization scattering on DIII-D. Rev Sci Instrum 2018; 89:10H113. [PMID: 30399840 DOI: 10.1063/1.5036791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Cross-polarization scattering (CPS) provides localized magnetic fluctuation ( B ̃ ) measurements in fusion plasmas based on the process where B ̃ scatters electromagnetic radiation into the orthogonal polarization. The CPS system on DIII-D utilizes the probe beam of a Doppler backscattering (DBS) diagnostic combined with a cross-view CPS receiver system, which allows simultaneous density and B ̃ measurements with good spatial and wavenumber coverage. The interpretation of the signals is challenging due to the complex plasma propagation of the DBS probe beam and CPS receive beams. A synthetic diagnostic for CPS is therefore essential to interpret data and perform detailed validation tests of non-linear turbulence simulations. This work reports a first step toward a synthetic diagnostic for CPS utilizing GENRAY, a 3-D ray tracing code, to simulate the propagation of the probe and scattered rays. The local B ̃ wavenumber is calculated from the local O- and X-mode wavenumbers using the wave vector matching scattering condition. The CPS wavenumber values and spatial locations are determined by a complex consideration that includes the local density and B ̃ level, receive antenna pattern and orientation, scattering volume, wavenumber values detected at the various scattering centers, and alignment of the magnetic wave vector with the plane perpendicular to the magnetic field. The issue of a spurious CPS signal due to polarization mismatches for launch and receive is also discussed. It is suggested that simultaneous O- and X-mode DBS measurements should be utilized for better understanding of the CPS signal contamination when the cutoff locations for both polarizations are close.
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Affiliation(s)
- G Wang
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - T L Rhodes
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - N A Crocker
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - W A Peebles
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - K Barada
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
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Rhodes TL, Lantsov R, Wang G, Ellis R, Peebles WA. Optimized quasi-optical cross-polarization scattering system for the measurement of magnetic turbulence on the DIII-D tokamak. Rev Sci Instrum 2018; 89:10H107. [PMID: 30399735 DOI: 10.1063/1.5035427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Simulations and laboratory tests are used to design and optimize a quasi-optical system for cross-polarization scattering (CPS) measurements of magnetic turbulence on the DIII-D tokamak. The CPS technique uses a process where magnetic turbulence scatters electromagnetic radiation into the perpendicular polarization enabling a local measurement of the perturbing magnetic fluctuations. This is a challenging measurement that addresses the contribution of magnetic turbulence to anomalous thermal transport in fusion research relevant plasmas. The goal of the new quasi-optical design is to demonstrate the full spatial and wavenumber capabilities of the CPS diagnostic. The approach used consists of independently controlled and in vacuo aiming systems for the probe and scattered beams (55-75 GHz).
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Affiliation(s)
- T L Rhodes
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - R Lantsov
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - G Wang
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - R Ellis
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - W A Peebles
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
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Rhodes TL, Barada K, Peebles WA, Crocker NA. Simultaneous measurement of magnetic and density fluctuations via cross-polarization scattering and Doppler backscattering on the DIII-D tokamak. Rev Sci Instrum 2016; 87:11E726. [PMID: 27910380 DOI: 10.1063/1.4960601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An upgraded cross-polarization scattering (CPS) system for the simultaneous measurement of internal magnetic fluctuations B̃ and density fluctuations ñ is presented. The system has eight radial quadrature channels acquired simultaneously with an eight-channel Doppler backscattering system (measures density fluctuations ñ and flows). 3-D ray tracing calculations based on the GENRAY ray tracing code are used to illustrate the scattering and geometric considerations involved in the CPS implementation on DIII-D. A unique quasi-optical design and IF electronics system allow direct comparison of B̃ and ñ during dynamic or transient plasma events (e.g., Edge Localized Modes or ELMs, L to H-mode transitions, etc.). The system design allows the interesting possibility of both magnetic-density (B̃-ñ) fluctuation and magnetic-temperature (B̃-T̃) fluctuation cross-phase measurements suitable for detailed tests of turbulence simulations.
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Affiliation(s)
- T L Rhodes
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - K Barada
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - W A Peebles
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
| | - N A Crocker
- Physics and Astronomy Department, University of California, Los Angeles, California 90098, USA
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Sung C, Peebles WA, Wannberg C, Rhodes TL, Nguyen X, Lantsov R, Bardóczi L. A frequency tunable, eight-channel correlation ECE system for electron temperature turbulence measurements on the DIII-D tokamak. Rev Sci Instrum 2016; 87:11E123. [PMID: 27910687 DOI: 10.1063/1.4961296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A new eight-channel correlation electron cyclotron emission diagnostic has recently been installed on the DIII-D tokamak to study both turbulent and coherent electron temperature fluctuations under various plasma conditions and locations. This unique system is designed to cover a broad range of operation space on DIII-D (1.6-2.1 T, detection frequency: 72-108 GHz) via four remotely selected local oscillators (80, 88, 96, and 104 GHz). Eight radial locations are measured simultaneously in a single discharge covering as much as half the minor radius. In this paper, we present design details of the quasi-optical system, the receiver, as well as representative data illustrating operation of the system.
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Affiliation(s)
- C Sung
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - W A Peebles
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - C Wannberg
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - T L Rhodes
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - X Nguyen
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - R Lantsov
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
| | - L Bardóczi
- Department of Physics and Astronomy, University of California, Los Angeles, California 90098, USA
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