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Liu X, Domier CW, Dannenberg J, Zhu Y, Sirigiri JR, Ren Y, Stratton B, Luhmann NC. The National Spherical Torus Experiment-Upgrade poloidal high-k scattering system pitch angle design modifications. Rev Sci Instrum 2022; 93:103509. [PMID: 36319363 DOI: 10.1063/5.0099912] [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: 05/19/2022] [Accepted: 08/23/2022] [Indexed: 06/16/2023]
Abstract
A 693 GHz, eight-channel, poloidal high-k (k refers to wavenumber) collective scattering system is under development for the National Spherical Torus Experiment-Upgrade device. It will replace the previous 280 GHz, five-channel, tangential scattering system to study high-k electron density fluctuations, thereby providing a measurement of the kθ-spectrum of both electron temperature gradient and ion temperature gradient modes. A tool is under development to calculate the wavenumber that exists in the presence of strong magnetic pitch angles. We use this tool to motivate a new receiver optical design for significantly improved performance, details of which are presented herein.
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Affiliation(s)
- X Liu
- University of California at Davis, 1 Shields Ave., Davis, California 95616, USA
| | - C W Domier
- University of California at Davis, 1 Shields Ave., Davis, California 95616, USA
| | - J Dannenberg
- University of California at Davis, 1 Shields Ave., Davis, California 95616, USA
| | - Y Zhu
- University of California at Davis, 1 Shields Ave., Davis, California 95616, USA
| | - J R Sirigiri
- Bridge 12 Technologies, Inc., 37 Loring Drive, Framingham, Massachusetts 01702, USA
| | - Y Ren
- Princeton Plasma Physics Laboratory, 100 Stellarator Rd., Princeton, New Jersey 08540, USA
| | - B Stratton
- Princeton Plasma Physics Laboratory, 100 Stellarator Rd., Princeton, New Jersey 08540, USA
| | - N C Luhmann
- University of California at Davis, 1 Shields Ave., Davis, California 95616, USA
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2
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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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3
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Domier CW, Zhu Y, Dannenberg J, Luhmann NC. A next generation ultra short pulse reflectometry (USPR) diagnostic. Rev Sci Instrum 2021; 92:034714. [PMID: 33820035 DOI: 10.1063/5.0040724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
Ultrashort Pulse Reflectometry (USPR) is a plasma diagnostic technique involving the propagation and reflection of ultrashort duration (∼few ns) chirps. The reflected packets pass through a multichannel filter with time-of-flight measurements performed on each of the filtered packets. A next generation USPR system is under development, spanning 28-75 GHz, for use on compact, short duration, magnetically confined fusion devices. This system presents a dramatic increase in performance compared with an earlier USPR system employed on the LLNL Sustained Spheromak Physics Experiment device more than a decade ago. The new system replaces upconverting mixers with higher power active multiplier chains to generate mm-wave transmitter chirps, with custom time-of-flight electronics reducing the time per measurement by a factor of 3X. Finally, the system is equipped with a field programmable gate array for data acquisition and analysis.
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Affiliation(s)
- C W Domier
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - Y Zhu
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - J Dannenberg
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
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Zhu Y, Yu JH, Yu G, Ye Y, Tobias B, Diallo A, Kramer G, Ren Y, Domier CW, Li X, Luo C, Chen M, Chen Y, Luhmann NC. W-band system-on-chip electron cyclotron emission imaging system on DIII-D. Rev Sci Instrum 2020; 91:093504. [PMID: 33003819 DOI: 10.1063/5.0018082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Monolithic, millimeter-wave "system-on-chip" (SoC) technology has been employed in heterodyne receiver integrated circuit radiometers in a newly developed Electron Cyclotron Emission Imaging (ECEI) system on the DIII-D tokamak for 2D electron temperature profile and fluctuation evolution diagnostics. A prototype module operating in the E-band (72 GHz-80 GHz) was first employed in a 2 × 10 element array that demonstrated significant improvements over the previous quasi-optical Schottky diode mixer arrays during the 2018 operational campaign of the DIII-D tokamak. For compatibility with International Thermonuclear Experimental Reactor relevant scenarios on DIII-D, the SoC ECEI system was upgraded with 20 horn-waveguide receiver modules. Each individual module contains a University of California Davis designed W-band (75 GHz-110 GHz) receiver die that integrates a broadband low noise amplifier, a double balanced down-converting mixer, and a ×4 multiplier on the local oscillator (LO) chain. A ×2 multiplier and two IF amplifiers are packaged and selected to further boost the signal strength and downconvert the signal frequency. The upgraded W-band array exhibits >30 dB additional gain and 20× improvement in noise temperature compared with the previous Schottky diode radio frequency mixer input systems; an internal 8 times multiplier chain is used to bring down the LO frequency below 12 GHz, thereby obviating the need for a large aperture for quasi-optical LO coupling and replacing it with coaxial connectors. Horn-waveguide shielding housing avoids out-of-band noise interference on each individual module. The upgraded ECEI system plays an important role for absolute electron temperature evolution and fluctuation measurements for edge and core region transport physics studies.
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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
| | - 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
| | - 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
| | - Y Chen
- University of California Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California Davis, Davis, California 95616, USA
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5
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Yu JH, Chang YT, Lin KY, Chang CC, Chang SF, Ye Y, Pham AV, Tobias BJ, Zhu Y, Domier CW, Luhmann NC. Millimeter-wave system-on-chip advancement for fusion plasma diagnostics. Rev Sci Instrum 2018; 89:10H108. [PMID: 30399905 DOI: 10.1063/1.5035559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/08/2018] [Indexed: 06/08/2023]
Abstract
Recent advances in radio-frequency system-on-chip technology have provided mm-wave fusion plasma diagnostics with the capability to overcome major challenges such as space inefficiency, inflexible installation, sensitivity, susceptibility to EMI, and prohibitively high cost of conventional discrete component assemblies as higher imaging resolution and data accuracy are achieved by increasing the number of channels. Nowadays, shrinking transistor gate lengths on fabrication techniques have enabled hundreds of GHz operation, which is suitable for millimeter-wave diagnostics on current and future tokamaks. The Davis Millimeter Wave Research Center (DMRC) has successfully developed V-band (55-75 GHz) transmitter and receiver chips for Microwave Imaging Reflectometer (MIR) instruments. The transmitter can illuminate 8 different frequencies simultaneously within 55-75 GHz. Moreover, the receiver has the capability to amplify the reflected signal (>30 dB) while offering 10-30× reduction in noise temperature compared to current MIR instruments. Plasma diagnostics requires ultra-wideband (more than 20 GHz) operation which is approximately nine times wider bandwidth than the recent commercial impetus for communication systems. Current efforts are underway for gallium-arsenide monolithic microwave integrated circuit receiver chips at W-band (75-110 GHz) and F-band (90-140 GHz) permitting measurements at higher toroidal magnetic fields.
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Affiliation(s)
- J-H Yu
- University of California, Davis, California 95616, USA
| | - Y-T Chang
- University of California, Davis, California 95616, USA
| | - K-Y Lin
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - C-C Chang
- Department of Electrical Engineering, National Chung-Cheng University, Chiayi 62102, Taiwan
| | - S-F Chang
- Department of Electrical Engineering, National Chung-Cheng University, Chiayi 62102, Taiwan
| | - Y Ye
- University of California, Davis, California 95616, USA
| | - A V Pham
- University of California, Davis, California 95616, USA
| | - B J Tobias
- Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
| | - Y Zhu
- University of California, Davis, California 95616, USA
| | - C W Domier
- University of California, Davis, California 95616, USA
| | - N C Luhmann
- University of California, Davis, California 95616, USA
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6
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Barchfeld R, Domier CW, Ren Y, Ellis R, Riemenschneider P, Allen N, Kaita R, Stratton B, Dannenberg J, Zhu Y, Luhmann NC. The high- k poloidal scattering system for NSTX-U. Rev Sci Instrum 2018; 89:10C114. [PMID: 30399655 DOI: 10.1063/1.5035410] [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: 06/25/2018] [Indexed: 06/08/2023]
Abstract
An 8-channel, high-k poloidal far-infrared (FIR) scattering system is under development for the National Spherical Torus eXperiment Upgrade (NSTX-U). The 693 GHz poloidal scattering system replaces a 5-channel, 280 GHz high-k toroidal scattering system to study high-k electron density fluctuations on NSTX-U. The FIR probe beam launched from Bay G is aimed toward Bay L, where large aperture optics collect radiation at 8 simultaneous scattering angles ranging from 2° to 15°. The reduced wavelength in the poloidal system results in less refraction, and coupled with a new poloidal scattering geometry, extends measurement of poloidal wavenumbers from the previous limit of 7 cm-1 up to >40 cm-1. Steerable launch optics coupled with receiver optics that can be remotely translated in 5 axes allow the scattering volume to be placed from r/a = 0.1 out to the pedestal region (r/a ∼ 0.99) and allow for both upward and downward scattering to cover different regions of the 2D fluctuation spectrum.
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Affiliation(s)
- R Barchfeld
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - Y Ren
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Ellis
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - P Riemenschneider
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N Allen
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Kaita
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - B Stratton
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J Dannenberg
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - Y Zhu
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
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7
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Zhu Y, Ye Y, Yu JH, Tobias B, Pham AV, Wang Y, Luo C, Domier CW, Kramer G, Ren Y, Diallo A, Nazikian R, Chen M, Yu G, Luhmann NC. Liquid crystal polymer receiver modules for electron cyclotron emission imaging on the DIII-D tokamak. Rev Sci Instrum 2018; 89:10H120. [PMID: 30399858 DOI: 10.1063/1.5035373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
A new generation of millimeter-wave heterodyne imaging receiver arrays has been developed and demonstrated on the DIII-D electron cyclotron emission imaging (ECEI) system. Improved circuit integration, improved noise performance, and enhanced shielding from out-of-band emission are made possible by using advanced liquid crystal polymer (LCP) substrates and monolithic microwave integrated circuit (MMIC) receiver chips. This array exhibits ∼15 dB additional gain and >30× reduction in noise temperature compared to previous generation ECEI arrays. Each LCP horn-waveguide module houses a 3 × 3 mm GaAs MMIC receiver chip, which consists of a low noise millimeter-wave preamplifier, balanced mixer, and IF amplifier together with a local oscillator multiplier chain driven at ∼12 GHz. A proof-of-principle partial LCP instrument with 5 poloidal channels was installed on DIII-D in 2017, with a full proof-of-principle system (20 poloidal × 8 radial channels) installed and commissioned in early 2018. The enhanced shielding of the LCP modules is seen to greatly reduce the sensitivity of ECEI signals to out-of-band microwave noise which has plagued previous ECEI studies on DIII-D. The LCP ECEI system is expected to be a valuable diagnostic tool for pedestal region measurements, focusing particularly on electron temperature evolution during edge localized mode bursting.
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Affiliation(s)
- Y Zhu
- University of California Davis, Davis, California 95616, USA
| | - Y Ye
- University of California Davis, Davis, California 95616, USA
| | - J-H Yu
- University of California Davis, Davis, California 95616, USA
| | - B Tobias
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A-V Pham
- University of California Davis, Davis, California 95616, USA
| | - Y Wang
- University of California Davis, Davis, California 95616, USA
| | - C Luo
- University of California Davis, Davis, California 95616, USA
| | - C W Domier
- University of California Davis, Davis, California 95616, USA
| | - G Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - Y Ren
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Diallo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M Chen
- University of California Davis, Davis, California 95616, USA
| | - G Yu
- University of California Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California Davis, Davis, California 95616, USA
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8
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Wan B, Yu C, Philippe P, Luhmann NC, Ang T, Domier CW, Gao B, Gentle K, Huang H, Li E, Ling B, Liu W, Liu Y, Prater R, Rowan W, Shen Z, Taylor G, Tobias BJ, Wang J, Wang J, Wen Y, Xia Z, Xiang H, Xie J, Xu M, Xu X. Electron Cyclotron Heating Program and Electron Cyclotron Emission Diagnostics on the EAST and HT-7 Superconducting Tokamaks. Fusion Science and Technology 2017. [DOI: 10.13182/fst11-a11726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Baonian Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Changxuan Yu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Perry Philippe
- University of Texas at Austin, Fusion Research Center, Austin, Texas 78712
| | - N. C. Luhmann
- University of California, Department of Applied Science, Davis, California 95616
| | - Ti Ang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - C. W. Domier
- University of California, Department of Applied Science, Davis, California 95616
| | - Binxi Gao
- University of Science and Technology of China, Hefei, China
| | - Kenneth Gentle
- University of Texas at Austin, Fusion Research Center, Austin, Texas 78712
| | - He Huang
- University of Texas at Austin, Fusion Research Center, Austin, Texas 78712
| | - Erzhong Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Bili Ling
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Wandong Liu
- University of Science and Technology of China, Hefei, China
| | - Yong Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Ron Prater
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - William Rowan
- University of Texas at Austin, Fusion Research Center, Austin, Texas 78712
| | - Zuowei Shen
- University of California, Department of Applied Science, Davis, California 95616
| | - Gary Taylor
- Princeton University, Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - Benjamin John Tobias
- University of California, Department of Applied Science, Davis, California 95616
| | - Jian Wang
- University of California, Department of Applied Science, Davis, California 95616
| | - Jun Wang
- University of Science and Technology of China, Hefei, China
| | - Yizhi Wen
- University of Science and Technology of China, Hefei, China
| | - Zhenggang Xia
- University of California, Department of Applied Science, Davis, California 95616
| | - Han Xiang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - Jinlin Xie
- University of Science and Technology of China, Hefei, China
| | - Ming Xu
- University of Science and Technology of China, Hefei, China
| | - Xiaoyuan Xu
- University of Science and Technology of China, Hefei, China
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Donné AJH, de Bock MFM, Classen IGJ, Von Hellermann MG, Jakubowska K, Jaspers R, Barth CJ, Van Der Meiden HJ, Oyevaar T, Van De Pol MJ, Varshney SK, Bertschinger G, Biel W, Busch C, Finken KH, Koslowski HR, KrÄmer-Flecken A, Kreter A, Liang Y, Oosterbeek H, Zimmermann O, Telesca G, Verdoolaege G, Domier CW, Luhmann NC, Mazzucato E, Munsat T, Park H, Kantor M, Kouprienko D, Alexeev A, Ohdachi S, Korsholm S, Woskov P, Bindslev H, Meo F, Michelsen PK, Michelsen S, Nielsen SK, Tsakadze E, Shmaenok L. Overview of Core Diagnostics for TEXTOR. Fusion Science and Technology 2017. [DOI: 10.13182/fst05-a702] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A. J. H. Donné
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - M. F. M. de Bock
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - I. G. J. Classen
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - M. G. Von Hellermann
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - K. Jakubowska
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - R. Jaspers
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - C. J. Barth
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - H. J. Van Der Meiden
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - T. Oyevaar
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - M. J. Van De Pol
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - S. K. Varshney
- FOM-Institute for Plasma Physics Rijnhuizen Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
| | - G. Bertschinger
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - W. Biel
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - C. Busch
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - K. H. Finken
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - H. R. Koslowski
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - A. KrÄmer-Flecken
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - A. Kreter
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - Y. Liang
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - H. Oosterbeek
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | - O. Zimmermann
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster D-52425 Jülich, Germany
| | | | | | - C. W. Domier
- University of California at Davis, Davis, California
| | - N. C. Luhmann
- University of California at Davis, Davis, California
| | - E. Mazzucato
- Princeton Plasma Physics Laboratory, Princeton, New Jersey
| | - T. Munsat
- Princeton Plasma Physics Laboratory, Princeton, New Jersey
| | - H. Park
- Princeton Plasma Physics Laboratory, Princeton, New Jersey
| | - M. Kantor
- Ioffe Physico-Technical Institute, St. Petersburg, Russia
| | - D. Kouprienko
- Ioffe Physico-Technical Institute, St. Petersburg, Russia
| | | | - S. Ohdachi
- National Institute for Fusion Studies, Toki, Japan
| | - S. Korsholm
- Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - P. Woskov
- Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | - F. Meo
- Risø National Laboratory, Roskilde, Denmark
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10
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Zhu YL, Xie JL, Yu CX, Zhao ZL, Gao BX, Chen DX, Liu WD, Liao W, Qu CM, Luo C, Hu X, Spear AG, Luhmann NC, Domier CW, Chen M, Ren X, Tobias BJ. Millimeter-wave imaging diagnostics systems on the EAST tokamak (invited). Rev Sci Instrum 2016; 87:11D901. [PMID: 27910310 DOI: 10.1063/1.4959162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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
Millimeter-wave imaging diagnostics, with large poloidal span and wide radial range, have been developed on the EAST tokamak for visualization of 2D electron temperature and density fluctuations. A 384 channel (24 poloidal × 16 radial) Electron Cyclotron Emission Imaging (ECEI) system in F-band (90-140 GHz) was installed on the EAST tokamak in 2012 to provide 2D electron temperature fluctuation images with high spatial and temporal resolution. A co-located Microwave Imaging Reflectometry (MIR) will be installed for imaging of density fluctuations by December 2016. This "4th generation" MIR system has eight independent frequency illumination beams in W-band (75-110 GHz) driven by fast tuning synthesizers and active multipliers. Both of these advanced millimeter-wave imaging diagnostic systems have applied the latest techniques. A novel design philosophy "general optics structure" has been employed for the design of the ECEI and MIR receiver optics with large aperture. The extended radial and poloidal coverage of ECEI on EAST is made possible by innovations in the design of front-end optics. The front-end optical structures of the two imaging diagnostics, ECEI and MIR, have been integrated into a compact system, including the ECEI receiver and MIR transmitter and receiver. Two imaging systems share the same mid-plane port for simultaneous, co-located 2D fluctuation measurements of electron density and temperature. An intelligent remote-control is utilized in the MIR electronics systems to maintain focusing at the desired radial region even with density variations by remotely tuning the probe frequencies in about 200 μs. A similar intelligent technique has also been applied on the ECEI IF system, with remote configuration of the attenuations for each channel.
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Affiliation(s)
- Y L Zhu
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - J L Xie
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - C X Yu
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - Z L Zhao
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - B X Gao
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - D X Chen
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - W D Liu
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - W Liao
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - C M Qu
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - C Luo
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - X Hu
- University of California, Davis, California 95616, USA
| | - A G Spear
- University of California, Davis, California 95616, USA
| | - N C Luhmann
- University of California, Davis, California 95616, USA
| | - C W Domier
- University of California, Davis, California 95616, USA
| | - M Chen
- University of California, Davis, California 95616, USA
| | - X Ren
- University of California, Davis, California 95616, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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11
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Tobias B, Domier CW, Luhmann NC, Luo C, Mamidanna M, Phan T, Pham AV, Wang Y. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry. Rev Sci Instrum 2016; 87:11E103. [PMID: 27910660 DOI: 10.1063/1.4959273] [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
The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.
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Affiliation(s)
- B Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C W Domier
- University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California at Davis, Davis, California 95616, USA
| | - C Luo
- University of California at Davis, Davis, California 95616, USA
| | - M Mamidanna
- University of California at Davis, Davis, California 95616, USA
| | - T Phan
- University of California at Davis, Davis, California 95616, USA
| | - A-V Pham
- University of California at Davis, Davis, California 95616, USA
| | - Y Wang
- University of California at Davis, Davis, California 95616, USA
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12
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Scott ER, Barchfeld R, Riemenschneider P, Domier CW, Muscatello CM, Sohrabi M, Kaita R, Ren Y, Luhmann NC. Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U. Rev Sci Instrum 2016; 87:11E114. [PMID: 27910494 DOI: 10.1063/1.4960415] [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
The Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment-Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.
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Affiliation(s)
- E R Scott
- Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616, USA
| | - R Barchfeld
- Department of Applied Science, University of California, Davis, California 95616, USA
| | - P Riemenschneider
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | | | - M Sohrabi
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - R Kaita
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - Y Ren
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
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13
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Pan XM, Yang ZJ, Ma XD, Zhu YL, Luhmann NC, Domier CW, Ruan BW, Zhuang G. Design of the 2D electron cyclotron emission imaging instrument for the J-TEXT tokamak. Rev Sci Instrum 2016; 87:11E106. [PMID: 27910430 DOI: 10.1063/1.4959875] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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 2D Electron Cyclotron Emission Imaging (ECEI) diagnostic is being developed for the J-TEXT tokamak. It will provide the 2D electron temperature information with high spatial, temporal, and temperature resolution. The new ECEI instrument is being designed to support fundamental physics investigations on J-TEXT including MHD, disruption prediction, and energy transport. The diagnostic contains two dual dipole antenna arrays corresponding to F band (90-140 GHz) and W band (75-110 GHz), respectively, and comprises a total of 256 channels. The system can observe the same magnetic surface at both the high field side and low field side simultaneously. An advanced optical system has been designed which permits the two arrays to focus on a wide continuous region or two radially separate regions with high imaging spatial resolution. It also incorporates excellent field curvature correction with field curvature adjustment lenses. An overview of the diagnostic and the technical progress including the new remote control technique are presented.
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Affiliation(s)
- X M Pan
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Z J Yang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - X D Ma
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Y L Zhu
- School of Physics, University of Science and Technology of China, Anhui 230026, China
| | - N C Luhmann
- Davis Millimeter Wave Research Center, University of California, Davis, California 95616, USA
| | - C W Domier
- Davis Millimeter Wave Research Center, University of California, Davis, California 95616, USA
| | - B W Ruan
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - G Zhuang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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14
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Jiang M, Shi ZB, Domier CW, Luhmann NC, Zhong WL, Chen W, Liu ZT, Ding XT, Yang QW, Zhang BY, Yang ZC, Shi PW, Liu Y, Fu BZ, Xu Y. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak. Rev Sci Instrum 2015; 86:076107. [PMID: 26233421 DOI: 10.1063/1.4927072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.
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Affiliation(s)
- M Jiang
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Z B Shi
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - W L Zhong
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - W Chen
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Z T Liu
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - X T Ding
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Q W Yang
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - B Y Zhang
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Z C Yang
- School of Physics and Chemistry, Xihua University, Chengdu 610039, China
| | - P W Shi
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Y Liu
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - B Z Fu
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
| | - Y Xu
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, China
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15
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Yun GS, Lee W, Choi MJ, Lee J, Kim M, Leem J, Nam Y, Choe GH, Park HK, Park H, Woo DS, Kim KW, Domier CW, Luhmann NC, Ito N, Mase A, Lee SG. Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR. Rev Sci Instrum 2014; 85:11D820. [PMID: 25430233 DOI: 10.1063/1.4890401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A second electron cyclotron emission imaging (ECEI) system has been installed on the KSTAR tokamak, toroidally separated by 1/16th of the torus from the first ECEI system. For the first time, the dynamical evolutions of MHD instabilities from the plasma core to the edge have been visualized in quasi-3D for a wide range of the KSTAR operation (B0 = 1.7∼3.5 T). This flexible diagnostic capability has been realized by substantial improvements in large-aperture quasi-optical microwave components including the development of broad-band polarization rotators for imaging of the fundamental ordinary ECE as well as the usual 2nd harmonic extraordinary ECE.
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Affiliation(s)
- G S Yun
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - W Lee
- Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - M J Choi
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - M Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J Leem
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Y Nam
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - G H Choe
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - H K Park
- Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - H Park
- School of Electrical Engineering, Kyungpook National University, Daegu 702-701, Korea
| | - D S Woo
- School of Electrical Engineering, Kyungpook National University, Daegu 702-701, Korea
| | - K W Kim
- School of Electrical Engineering, Kyungpook National University, Daegu 702-701, Korea
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N Ito
- KASTEC, Kyushu University, Kasuga-shi, Fukuoka 812-8581, Japan
| | - A Mase
- Ube National College of Technology, Ube-shi, Yamaguchi 755-8555, Japan
| | - S G Lee
- National Fusion Research Institute, Daejeon 305-333, Korea
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16
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Ren X, Domier CW, Kramer G, Luhmann NC, Muscatello CM, Shi L, Tobias BJ, Valeo E. Process to generate a synthetic diagnostic for microwave imaging reflectometry with the full-wave code FWR2D. Rev Sci Instrum 2014; 85:11D863. [PMID: 25430276 DOI: 10.1063/1.4895100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A synthetic microwave imaging reflectometer (MIR) diagnostic employing the full-wave reflectometer code (FWR2D) has been developed and is currently being used to guide the design of real systems, such as the one recently installed on DIII-D. The FWR2D code utilizes real plasma profiles as input, and it is combined with optical simulation tools for synthetic diagnostic signal generation. A detailed discussion of FWR2D and the process to generate the synthetic signal are presented in this paper. The synthetic signal is also compared to a prescribed density fluctuation spectrum to quantify the imaging quality. An example is presented with H-mode-like plasma profiles derived from a DIII-D discharge, where the MIR focal is located in the pedestal region. It is shown that MIR is suitable for diagnosing fluctuations with poloidal wavenumber up to 2.0 cm(-1) and fluctuation amplitudes less than 5%.
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Affiliation(s)
- X Ren
- Millimeter and Microwave Research Center, University of California at Davis, Davis, California 95616, USA
| | - C W Domier
- Millimeter and Microwave Research Center, University of California at Davis, Davis, California 95616, USA
| | - G Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - N C Luhmann
- Millimeter and Microwave Research Center, University of California at Davis, Davis, California 95616, USA
| | - C M Muscatello
- Millimeter and Microwave Research Center, University of California at Davis, Davis, California 95616, USA
| | - L Shi
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - E Valeo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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17
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Muscatello CM, Domier CW, Hu X, Kramer GJ, Luhmann NC, Ren X, Riemenschneider P, Spear A, Tobias BJ, Valeo E, Yu L. Technical overview of the millimeter-wave imaging reflectometer on the DIII-D tokamak (invited). Rev Sci Instrum 2014; 85:11D702. [PMID: 25430212 DOI: 10.1063/1.4889735] [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: 06/04/2023]
Abstract
The two-dimensional mm-wave imaging reflectometer (MIR) on DIII-D is a multi-faceted device for diagnosing electron density fluctuations in fusion plasmas. Its multi-channel, multi-frequency capabilities and high sensitivity permit visualization and quantitative diagnosis of density perturbations, including correlation length, wavenumber, mode propagation velocity, and dispersion. The two-dimensional capabilities of MIR are made possible with 12 vertically separated sightlines and four-frequency operation (corresponding to four radial channels). The 48-channel DIII-D MIR system has a tunable source that can be stepped in 500 μs increments over a range of 56 to 74 GHz. An innovative optical design keeps both on-axis and off-axis channels focused at the cutoff surface, permitting imaging over an extended poloidal region. The integrity of the MIR optical design is confirmed by comparing Gaussian beam calculations to laboratory measurements of the transmitter beam pattern and receiver antenna patterns. Measurements are presented during the density ramp of a plasma discharge to demonstrate unfocused and focused MIR signals.
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Affiliation(s)
- C M Muscatello
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - X Hu
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - G J Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - X Ren
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - P Riemenschneider
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - A Spear
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - E Valeo
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
| | - L Yu
- Department of Electrical and Computer Engineering, University of California Davis, 347 Memorial Un, Davis, California 95616, USA
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18
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Spear AG, Domier CW, Hu X, Muscatello CM, Ren X, Tobias BJ, Luhmann NC. 2D microwave imaging reflectometer electronics. Rev Sci Instrum 2014; 85:11D834. [PMID: 25430247 DOI: 10.1063/1.4891047] [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: 06/04/2023]
Abstract
A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.
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Affiliation(s)
- A G Spear
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
| | - C W Domier
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
| | - X Hu
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
| | - C M Muscatello
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
| | - X Ren
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - N C Luhmann
- Electrical & Computer Engineering, University of California, Davis, California 95616, USA
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19
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Classen IGJ, Domier CW, Luhmann NC, Bogomolov AV, Suttrop W, Boom JE, Tobias BJ, Donné AJH. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade. Rev Sci Instrum 2014; 85:11D833. [PMID: 25430246 DOI: 10.1063/1.4891061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments.
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Affiliation(s)
- I G J Classen
- FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein, The Netherlands
| | - C W Domier
- Department of Applied Science, University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- Department of Applied Science, University of California at Davis, Davis, California 95616, USA
| | - A V Bogomolov
- FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein, The Netherlands
| | - W Suttrop
- Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching, Germany
| | - J E Boom
- Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching, Germany
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - A J H Donné
- FOM-Institute DIFFER, Dutch Institute for Fundamental Energy Research, 3430 BE Nieuwegein, The Netherlands
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20
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Zhu Y, Zhao Z, Liu WD, Xie J, Hu X, Muscatello CM, Domier CW, Luhmann NC, Chen M, Ren X, Tobias BJ, Zhuang G, Yang Z. Optics design for J-TEXT ECE imaging with field curvature adjustment lens. Rev Sci Instrum 2014; 85:11D854. [PMID: 25430267 DOI: 10.1063/1.4893352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas. Of particular importance has been microwave electron cyclotron emission imaging (ECEI) for imaging Te fluctuations. Key to the success of ECEI is a large Gaussian optics system constituting a major portion of the focusing of the microwave radiation from the plasma to the detector array. Both the spatial resolution and observation range are dependent upon the imaging optics system performance. In particular, it is critical that the field curvature on the image plane is reduced to decrease crosstalk between vertical channels. The receiver optics systems for two ECEI on the J-TEXT device have been designed to ameliorate these problems and provide good performance with additional field curvature adjustment lenses with a meniscus shape to correct the aberrations from several spherical surfaces.
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Affiliation(s)
- Y Zhu
- School of Physics, University of Science and Technology of China, Anhui 230026, People's Republic of China
| | - Z Zhao
- School of Physics, University of Science and Technology of China, Anhui 230026, People's Republic of China
| | - W D Liu
- School of Physics, University of Science and Technology of China, Anhui 230026, People's Republic of China
| | - J Xie
- School of Physics, University of Science and Technology of China, Anhui 230026, People's Republic of China
| | - X Hu
- University of California at Davis, Davis, California 95616, USA
| | - C M Muscatello
- University of California at Davis, Davis, California 95616, USA
| | - C W Domier
- University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California at Davis, Davis, California 95616, USA
| | - M Chen
- University of California at Davis, Davis, California 95616, USA
| | - X Ren
- University of California at Davis, Davis, California 95616, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - G Zhuang
- College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Z Yang
- College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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21
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Tobias B, Grierson BA, Muscatello CM, Ren X, Domier CW, Luhmann NC, Zemedkun SE, Munsat TL, Classen IGJ. Phase-locking of magnetic islands diagnosed by ECE-imaging. Rev Sci Instrum 2014; 85:11D847. [PMID: 25430260 DOI: 10.1063/1.4892438] [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: 06/04/2023]
Abstract
Millimeter-wave imaging diagnostics identify phase-locking and the satisfaction of 3-wave coupling selection criteria among multiple magnetic island chains by providing a localized, internal measurement of the 2D power spectral density, S(ω, kpol). In high-confinement tokamak discharges, these interactions impact both plasma rotation and tearing stability. Nonlinear coupling among neoclassical tearing modes of different n-number, with islands not satisfying the poloidal mode number selection criterion ⟨m, m('), m - m(')⟩, contributes to a reduction in core rotation and flow shear in the vicinity of the modes.
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Affiliation(s)
- B Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - B A Grierson
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C M Muscatello
- Department of Electrical and Computer Engineering, Universtiy of California at Davis, Davis, California 95616, USA
| | - X Ren
- Department of Electrical and Computer Engineering, Universtiy of California at Davis, Davis, California 95616, USA
| | - C W Domier
- Department of Electrical and Computer Engineering, Universtiy of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, Universtiy of California at Davis, Davis, California 95616, USA
| | - S E Zemedkun
- Department of Electrical and Computer Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - T L Munsat
- Department of Electrical and Computer Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - I G J Classen
- Dutch Institute for Fundamental Energy Research-DIFFER, 3430 BE Nieuwegein, The Netherlands
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22
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Liu X, Zhao HL, Liu Y, Li EZ, Han X, Domier CW, Luhmann NC, Ti A, Hu LQ, Zhang XD. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak. Rev Sci Instrum 2014; 85:093508. [PMID: 25273727 DOI: 10.1063/1.4896047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems.
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Affiliation(s)
- X Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - H L Zhao
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - E Z Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - X Han
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - A Ti
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - X D Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
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23
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Han X, Liu X, Liu Y, Domier CW, Luhmann NC, Li EZ, Hu LQ, Gao X. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak. Rev Sci Instrum 2014; 85:073506. [PMID: 25085139 DOI: 10.1063/1.4891040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104-168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ~500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.
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Affiliation(s)
- X Han
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
| | - X Liu
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
| | - Y Liu
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
| | - E Z Li
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
| | - L Q Hu
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
| | - X Gao
- Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, People's Republic of China
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24
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Lee J, Yun GS, Lee JE, Kim M, Choi MJ, Lee W, Park HK, Domier CW, Luhmann NC, Sabbagh SA, Park YS, Lee SG, Bak JG. Toroidal mode number estimation of the edge-localized modes using the KSTAR 3-D electron cyclotron emission imaging system. Rev Sci Instrum 2014; 85:063505. [PMID: 24985817 DOI: 10.1063/1.4883180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new and more accurate technique is presented for determining the toroidal mode number n of edge-localized modes (ELMs) using two independent electron cyclotron emission imaging (ECEI) systems in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The technique involves the measurement of the poloidal spacing between adjacent ELM filaments, and of the pitch angle α* of filaments at the plasma outboard midplane. Equilibrium reconstruction verifies that α* is nearly constant and thus well-defined at the midplane edge. Estimates of n obtained using two ECEI systems agree well with n measured by the conventional technique employing an array of Mirnov coils.
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Affiliation(s)
- J Lee
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - G S Yun
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - J E Lee
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - M Kim
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - M J Choi
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - W Lee
- Pohang University of Science and Technology, Pohang 790-784, South Korea
| | - H K Park
- Ulsan National Institute of Science and Technology, Ulsan 689-798, South Korea
| | - C W Domier
- University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- University of California at Davis, Davis, California 95616, USA
| | - S A Sabbagh
- Columbia University, New York, New York 10027, USA
| | - Y S Park
- Columbia University, New York, New York 10027, USA
| | - S G Lee
- National Fusion Research Institute, Daejeon 305-333, South Korea
| | - J G Bak
- National Fusion Research Institute, Daejeon 305-333, South Korea
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25
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Lai J, Domier CW, Luhmann NC. Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems. Rev Sci Instrum 2014; 85:033501. [PMID: 24689579 DOI: 10.1063/1.4866652] [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: 06/03/2023]
Abstract
Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T(e) and n(e) fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ~60,000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50-75 GHz), significant improvement of noise temperature from the current 60,000 K to measured 4000 K has been obtained.
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Affiliation(s)
- J Lai
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - C W Domier
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA
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26
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Jiang M, Shi ZB, Che S, Domier CW, Luhmann NC, Hu X, Spear A, Liu ZT, Ding XT, Li J, Zhong WL, Chen W, Che YL, Fu BZ, Cui ZY, Sun P, Liu Y, Yang QW, Duan XR. Development of electron cyclotron emission imaging system on the HL-2A tokamak. Rev Sci Instrum 2013; 84:113501. [PMID: 24289395 DOI: 10.1063/1.4828671] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A 2D electron cyclotron emission imaging (ECEI) system has been developed for measurement of electron temperature fluctuations in the HL-2A tokamak. It is comprised of a front-end 24 channel heterodyne imaging array with a tunable RF range spanning 75-110 GHz, and a set of back-end ECEI electronics that together generate 24 × 8 = 192 channel images of the 2nd harmonic X-mode electron cyclotron emission from the HL-2A plasma. The simulated performance of the local oscillator (LO) optics and radio frequency (RF) optics is presented, together with the laboratory characterization results. The Gaussian beams from the LO optics are observed to properly cover the entire detector array. The ECE signals from the plasma are mixed with the LO signal in the array box, then delivered to the electronics system by low-loss microwave cables, and finally to the digitizers. The ECEI system can achieve temporal resolutions of ~μs, and spatial resolutions of 1 cm (radially) and 2 cm (poloidally).
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Affiliation(s)
- M Jiang
- Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041, China
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27
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Yun GS, Park HK, Lee W, Choi MJ, Choe GH, Park S, Bae YS, Lee KD, Yoon SW, Jeon YM, Domier CW, Luhmann NC, Tobias B, Donné AJH. Appearance and dynamics of helical flux tubes under electron cyclotron resonance heating in the core of KSTAR plasmas. Phys Rev Lett 2012; 109:145003. [PMID: 23083252 DOI: 10.1103/physrevlett.109.145003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Indexed: 06/01/2023]
Abstract
Dual (or sometimes multiple) flux tubes (DFTs) have been observed in the core of sawtoothing KSTAR tokamak plasmas with electron cyclotron resonance heating. The time evolution of the flux tubes visualized by a 2D electron cyclotron emission imaging diagnostic typically consists of four distinctive phases: (1) growth of one flux tube out of multiple small flux tubes during the initial buildup period following a sawtooth crash, resulting in a single dominant flux tube along the m/n=1/1 helical magnetic field lines, (2) sudden rapid growth of another flux tube via a fast heat transfer from the first one, resulting in approximately identical DFTs, (3) coalescence of the two flux tubes into a single m/n=1/1 flux tube resembling the internal kink mode in the normal sawteeth, which is explained by a model of two current-carrying wires confined on a flux surface, and (4) fast localized crash of the merged flux tube similar to the standard sawtooth crash. The dynamics of the DFTs implies that the internal kink mode is not a unique prerequisite to the sawtooth crash, providing a new insight on the control of the sawtooth.
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Affiliation(s)
- G S Yun
- POSTECH, Pohang 790-784, Korea.
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28
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Tobias BJ, Austin ME, Boom JE, Burrell KH, Classen IGJ, Domier CW, Luhmann NC, Nazikian R, Snyder PB. ECE-imaging of the H-mode pedestal (invited). Rev Sci Instrum 2012; 83:10E329. [PMID: 23126987 DOI: 10.1063/1.4733742] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A synthetic diagnostic has been developed that reproduces the highly structured electron cyclotron emission (ECE) spectrum radiated from the edge region of H-mode discharges. The modeled dependence on local perturbations of the equilibrium plasma pressure allows for interpretation of ECE data for diagnosis of local quantities. Forward modeling of the diagnostic response in this region allows for improved mapping of the observed fluctuations to flux surfaces within the plasma, allowing for the poloidal mode number of coherent structures to be resolved. In addition, other spectral features that are dependent on both T(e) and n(e) contain information about pedestal structure and the electron energy distribution of localized phenomena, such as edge filaments arising during edge-localized mode (ELM) activity.
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Affiliation(s)
- B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
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29
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Ren X, Tobias BJ, Che S, Domier CW, Luhmann NC, Muscatello CM, Kramer G, Valeo E. Evaluation of the operating space for density fluctuation measurements employing 2D imaging reflectometry. Rev Sci Instrum 2012; 83:10E338. [PMID: 23126996 DOI: 10.1063/1.4739076] [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: 06/01/2023]
Abstract
Microwave imaging reflectometry provides broad poloidal coverage as a density fluctuation measurement tool. 2D imaging systems are evaluated for DIII-D relevant conditions using a full-wave reflectometer code, FWR2D. Reasonable correlation of the synthetic diagnostic signal with density fluctuations at the plasma cutoff surface for a wide range of fluctuation parameters is evaluated and achieved for coherent oscillations; also the frequency spectra are compared for relevant fluctuations. The consequences of non-idealities inherent to imaging fluctuations away from the plasma midplane, where receiving antennas view the plasma cutoff at oblique angles, are evaluated for the optimization of these systems.
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Affiliation(s)
- X Ren
- University of California at Davis, Davis, California 95616, USA.
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30
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Yun GS, Lee W, Choi MJ, Lee J, Park HK, Tobias B, Domier CW, Luhmann NC, Donné AJH, Lee JH. Two-dimensional visualization of growth and burst of the edge-localized filaments in KSTAR H-mode plasmas. Phys Rev Lett 2011; 107:045004. [PMID: 21867016 DOI: 10.1103/physrevlett.107.045004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Indexed: 05/31/2023]
Abstract
The filamentary nature and dynamics of edge-localized modes (ELMs) in the KSTAR high-confinement mode plasmas have been visualized in 2D via electron cyclotron emission imaging. The ELM filaments rotating with a net poloidal velocity are observed to evolve in three distinctive stages: initial linear growth, interim quasisteady state, and final crash. The crash is initiated by a narrow fingerlike perturbation growing radially from a poloidally elongated filament. The filament bursts through this finger, leading to fast and collective heat convection from the edge region into the scrape-off layer, i.e., ELM crash.
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Affiliation(s)
- G S Yun
- POSTECH, Pohang, Republic of Korea
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31
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Ren Y, Kaye SM, Mazzucato E, Guttenfelder W, Bell RE, Domier CW, LeBlanc BP, Lee KC, Luhmann NC, Smith DR, Yuh H. Density gradient stabilization of electron temperature gradient driven turbulence in a spherical tokamak. Phys Rev Lett 2011; 106:165005. [PMID: 21599377 DOI: 10.1103/physrevlett.106.165005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Indexed: 05/30/2023]
Abstract
In this Letter we report the first clear experimental observation of density gradient stabilization of electron temperature gradient driven turbulence in a fusion plasma. It is observed that longer wavelength modes, k(⊥)ρ(s) ≲ 10, are most stabilized by density gradient, and the stabilization is accompanied by about a factor of 2 decrease in the plasma effective thermal diffusivity.
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Affiliation(s)
- Y Ren
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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32
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Tobias BJ, Classen IGJ, Domier CW, Heidbrink WW, Luhmann NC, Nazikian R, Park HK, Spong DA, Van Zeeland MA. Fast ion induced shearing of 2D Alfvén eigenmodes measured by electron cyclotron emission imaging. Phys Rev Lett 2011; 106:075003. [PMID: 21405522 DOI: 10.1103/physrevlett.106.075003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Indexed: 05/30/2023]
Abstract
Two-dimensional images of electron temperature perturbations are obtained with electron cyclotron emission imaging (ECEI) on the DIII-D tokamak and compared to Alfvén eigenmode structures obtained by numerical modeling using both ideal MHD and hybrid MHD-gyrofluid codes. While many features of the observations are found to be in excellent agreement with simulations using an ideal MHD code (NOVA), other characteristics distinctly reveal the influence of fast ions on the mode structures. These features are found to be well described by the nonperturbative hybrid MHD-gyrofluid model TAEFL.
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Affiliation(s)
- B J Tobias
- University of California, Davis, 95616, USA
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33
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Tsai WC, Domier CW, Lee KC, Luhmann NC, Kaita R, Park HK. NSTX far infrared tangential interferometer/polarimeter electronics upgrade. Rev Sci Instrum 2010; 81:10D526. [PMID: 21033881 DOI: 10.1063/1.3485103] [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: 05/30/2023]
Abstract
New electronics for the multichannel far infrared tangential interferometer/polarimeter system employed on the National Spherical Torus Experiment (NSTX) have greatly extended its capability to monitor high frequency density fluctuations. Such measurements are essential in understanding transport physics issues in NSTX as well as for the coming ITER device. The electronics, which were previously limited to ∼250 kHz, have been upgraded with a video bandwidth that extends to 4 MHz when operating as an interferometry-only configuration, and to ∼500 kHz when operating as a simultaneous interferometer/polarimeter system. Experimental details and test results of the new electronics are presented.
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Affiliation(s)
- W C Tsai
- Department of Electrical and Computer Engineering, University of California, Davis, California 95616, USA
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34
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Kim J, Lee KC, Kaita R, Phillips CK, Domier CW, Valeo E, Luhmann NC, Bonoli PT, Park H. Use of the Far Infrared Tangential Interferometer/Polarimeter diagnostic for the study of rf driven plasma waves on NSTX. Rev Sci Instrum 2010; 81:10D527. [PMID: 21033882 DOI: 10.1063/1.3499506] [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: 05/30/2023]
Abstract
A rf detection system for waves in the 30 MHz range has been constructed for the Far Infrared Tangential Interferometer/Polarimeter on National Spherical Torus Experiment (NSTX). It is aimed at monitoring high frequency density fluctuations driven by 30 MHz high harmonic fast wave fields. The levels of density fluctuations at various radial chords and antenna phase angles can be estimated using the electric field calculated by TORIC code and linearized continuity equation for the electron density. In this paper, the experimental arrangement for the detection of rf signal and preliminary results of simulation will be discussed.
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Affiliation(s)
- J Kim
- Department of Physics, POSTECH, Pohang, Gyeongbuk 790-784, Korea.
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35
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Lee W, Yun GS, Nam Y, Hong I, Kim JB, Park HK, Tobias B, Liang T, Domier CW, Luhmann NC. Comparative study between the reflective optics and lens based system for microwave imaging system on KSTAR. Rev Sci Instrum 2010; 81:10D932. [PMID: 21033960 DOI: 10.1063/1.3491189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Recently, two-dimensional microwave imaging diagnostics such as the electron cyclotron emission imaging (ECEI) system and microwave imaging reflectometry (MIR) have been developed to study magnetohydrodynamics instabilities and turbulence in magnetically confined plasmas. These imaging systems utilize large optics to collect passive emission or reflected radiation. The design of this optics can be classified into two different types: reflective or refractive optical systems. For instance, an ECEI/MIR system on the TEXTOR tokamak [Park et al., Rev. Sci. Instrum. 75, 3787 (2004)] employed the reflective optics which consisted of two large mirrors, while the TEXTOR ECEI upgrade [B. Tobias et al., Rev. Sci. Instrum. 80, 093502 (2009)] and systems on DIII-D, ASDEX-U, and KSTAR adopted refractive systems. Each system has advantages and disadvantages in the standing wave problem and optical aberrations. In this paper, a comparative study between the two optical systems has been performed in order to design a MIR system for KSTAR.
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Affiliation(s)
- W Lee
- POSTECH, Pohang, Gyeongbuk 790-784, Republic of Korea.
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36
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Classen IGJ, Boom JE, Suttrop W, Schmid E, Tobias B, Domier CW, Luhmann NC, Donné AJH, Jaspers RJE, de Vries PC, Park HK, Munsat T, García-Muñoz M, Schneider PA. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited). Rev Sci Instrum 2010; 81:10D929. [PMID: 21033957 DOI: 10.1063/1.3483214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfvén eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.
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Affiliation(s)
- I G J Classen
- Max Planck Institut für Plasmaphysik, 85748 Garching, Germany.
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37
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Park HK, Hong I, Kim M, Yun GS, Lee W, Kim J, Tobias B, Domier CW, Luhmann NC, Kim KW. Microwave imaging reflectometry studies for turbulence diagnostics on KSTAR. Rev Sci Instrum 2010; 81:10D933. [PMID: 21033961 DOI: 10.1063/1.3499606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The first prototype microwave imaging reflectometry (MIR) system [H. Park et al., Rev. Sci. Instrum. 74, 4239 (2004)] clearly demonstrated the shortcomings of conventional reflectometry when the probe beam encountered a large amplitude and/or high fluctuation wavenumber at the reflection layer in laboratory tests, the distinctive advantages shown in these tests were not fully realized in the plasma operation. To understand the discrepancies, the MIR system performance has been thoroughly investigated at POSTECH. In this paper, a possible cause of the MIR performance degradation on TEXTOR will be presented together with a concept of multifrequency MIR system design that will be developed for KSTAR.
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Affiliation(s)
- H K Park
- Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Korea.
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38
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Kong X, Domier CW, Luhmann NC. Antenna development for high field plasma imaging. Rev Sci Instrum 2010; 81:10D923. [PMID: 21033955 DOI: 10.1063/1.3479117] [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: 05/30/2023]
Abstract
Electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) are two microwave nonperturbing plasma visualization techniques that employ millimeter-wave imaging arrays with lens-coupled planar antennas, yielding time-resolved images of temperature (via ECEI) and electron density (via MIR) fluctuations within high temperature magnetic fusion plasmas. A series of new planar antennas have been developed that extend this technology to frequencies as high as 220 GHz for use on high field plasma devices with toroidal fields in excess of 3 T. Antenna designs are presented together with theoretical calculations, simulations, and experimental measurements.
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Affiliation(s)
- X Kong
- Department of Applied Science, University of California at Davis, Davis, California 95616, USA
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39
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Liang T, Tobias B, Kong X, Domier CW, Luhmann NC, Lee W, Yun GS, Park HK. Innovations in optical coupling of the KSTAR electron cyclotron emission imaging diagnostic. Rev Sci Instrum 2010; 81:10D909. [PMID: 21033941 DOI: 10.1063/1.3478637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The installation of a new electron cyclotron emission imaging diagnostic for the Korea Superconducting Tokamak Advanced Research (KSTAR) is underway, making use of a unique optical port cassette design, which allows placement of refractive elements inside the cryostat region without adverse effects. The result is unprecedented window access for the implementation of a state of the art imaging diagnostic. A dual-array optical design has been developed, capable of simultaneously imaging the high and low field sides of the plasma with independent features of focal plane translation, vertical zoom, and radial channel spacing. The number of translating optics has been minimized by making use of a zoom lens triplet and parabolic plasma facing lens for maximum channel uniformity over a continuous vertical zoom range of 3:1. The simulated performance of this design is presented along with preliminary laboratory characterization data.
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Affiliation(s)
- T Liang
- University of California at Davis, Davis, California 95616, USA.
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40
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Juhn JW, Lee KC, Hwang YS, Domier CW, Luhmann NC, Leblanc BP, Mueller D, Gates DA, Kaita R. Fringe-jump corrected far infrared tangential interferometer/polarimeter for a real-time density feedback control system of NSTX plasmas. Rev Sci Instrum 2010; 81:10D540. [PMID: 21033892 DOI: 10.1063/1.3492381] [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: 05/30/2023]
Abstract
The far infrared tangential interferometer/polarimeter (FIReTIP) of the National Spherical Torus Experiment (NSTX) has been set up to provide reliable electron density signals for a real-time density feedback control system. This work consists of two main parts: suppression of the fringe jumps that have been prohibiting the plasma density from use in the direct feedback to actuators and the conceptual design of a density feedback control system including the FIReTIP, control hardware, and software that takes advantage of the NSTX plasma control system (PCS). By investigating numerous shot data after July 2009 when the new electronics were installed, fringe jumps in the FIReTIP are well characterized, and consequently the suppressing algorithms are working properly as shown in comparisons with the Thomson scattering diagnostic. This approach is also applicable to signals taken at a 5 kHz sampling rate, which is a fundamental constraint imposed by the digitizers providing inputs to the PCS. The fringe jump correction algorithm, as well as safety and feedback modules, will be included as submodules either in the gas injection system category or a new category of density in the PCS.
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Affiliation(s)
- J-W Juhn
- Department of Nuclear Engineering, Seoul National University, Seoul 151-744, Korea.
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41
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Kim JB, Lee W, Yun GS, Park HK, Domier CW, Luhmann NC. Data acquisition and processing system of the electron cyclotron emission imaging system of the KSTAR tokamak. Rev Sci Instrum 2010; 81:10D931. [PMID: 21033959 DOI: 10.1063/1.3479023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A new innovative electron cyclotron emission imaging (ECEI) diagnostic system for the Korean Superconducting Tokamak Advanced Research (KSTAR) produces a large amount of data. The design of the data acquisition and processing system of the ECEI diagnostic system should consider covering the large data production and flow. The system design is based on the layered structure scalable to the future extension to accommodate increasing data demands. Software architecture that allows a web-based monitoring of the operation status, remote experiment, and data analysis is discussed. The operating software will help machine operators and users validate the acquired data promptly, prepare next discharge, and enhance the experiment performance and data analysis in a distributed environment.
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Affiliation(s)
- J B Kim
- Department of Physics, POSTECH, San-31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, South Korea.
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42
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Yun GS, Lee W, Choi MJ, Kim JB, Park HK, Domier CW, Tobias B, Liang T, Kong X, Luhmann NC, Donné AJH. Development of KSTAR ECE imaging system for measurement of temperature fluctuations and edge density fluctuations. Rev Sci Instrum 2010; 81:10D930. [PMID: 21033958 DOI: 10.1063/1.3483209] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The ECE imaging (ECEI) diagnostic tested on the TEXTOR tokamak revealed the sawtooth reconnection physics in unprecedented detail, including the first observation of high-field-side crash and collective heat transport [H. K. Park, N. C. Luhmann, Jr., A. J. H. Donné et al., Phys. Rev. Lett. 96, 195003 (2006)]. An improved ECEI system capable of visualizing both high- and low-field sides simultaneously with considerably better spatial coverage has been developed for the KSTAR tokamak in order to capture the full picture of core MHD dynamics. Direct 2D imaging of other MHD phenomena such as tearing modes, edge localized modes, and even Alfvén eigenmodes is expected to be feasible. Use of ECE images of the optically thin edge region to recover 2D electron density changes during L/H mode transitions is also envisioned, providing powerful information about the underlying physics. The influence of density fluctuations on optically thin ECE is discussed.
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Affiliation(s)
- G S Yun
- Pohang University of Science and Technology, Pohang, Gyungbuk 790-784, South Korea.
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Lei L, Tobias B, Domier CW, Luhmann NC, Kramer GJ, Valeo EJ, Lee W, Yun GS, Park HK. A synthetic diagnostic for the evaluation of new microwave imaging reflectometry diagnostics for DIII-D and KSTAR. Rev Sci Instrum 2010; 81:10D904. [PMID: 21033936 DOI: 10.1063/1.3464461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The first microwave imaging reflectometry (MIR) system for characterization of fluctuating plasma density has been implemented for the TEXTOR tokamak [H. Park et al., Rev. Sci. Instrum. 75, 3787 (2004)]; an improved MIR system will be installed on DIII-D and KSTAR. The central issue remains in preserving phase information by addressing antenna coupling between the reflection layer and the detector array in the presence of plasma turbulence. A synthetic diagnostic making use of coupled full-wave diffractive codes has been developed in geometries and applied to a variety of optical arrangements. The effectiveness of each scheme is quantitatively compared with respect to the fluctuation levels accessible in the simulation.
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Affiliation(s)
- L Lei
- University of California at Davis, Davis, California 95616, USA
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44
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Tobias B, Domier CW, Liang T, Kong X, Yu L, Yun GS, Park HK, Classen IGJ, Boom JE, Donné AJH, Munsat T, Nazikian R, Van Zeeland M, Boivin RL, Luhmann NC. Commissioning of electron cyclotron emission imaging instrument on the DIII-D tokamak and first data. Rev Sci Instrum 2010; 81:10D928. [PMID: 21033956 DOI: 10.1063/1.3460456] [Citation(s) in RCA: 6] [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: 05/30/2023]
Abstract
A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of T(e) fluctuations over radially distinct and reconfigurable regions, each with both vertical and radial zoom capability. A total of 320 (20 vertical×16 radial) channels are available. First data from this diagnostic demonstrate the acquisition of coherent electron temperature fluctuations as low as 0.1% with excellent clarity and spatial resolution. Details of the diagnostic features and capabilities are presented.
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Affiliation(s)
- B Tobias
- University of California at Davis, Davis, California 95616, USA.
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45
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Tobias B, Kong X, Liang T, Spear A, Domier CW, Luhmann NC, Classen IGJ, Boom JE, van de Pol MJ, Jaspers R, Donné AJH, Park HK, Munsat T. Advancements in electron cyclotron emission imaging demonstrated by the TEXTOR ECEI diagnostic upgrade. Rev Sci Instrum 2009; 80:093502. [PMID: 19791937 DOI: 10.1063/1.3233913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new TEXTOR electron cyclotron emission imaging system has been developed and employed, providing a diagnostic with new features and enhanced capabilities when compared to the legacy system it replaces. Optical coupling to the plasma has been completely redesigned, making use of new minilens arrays for reduced optical aberration and providing the new feature of vertical zoom, whereby the vertical coverage is now remotely adjustable on a shot-by-shot basis from 20-35 cm. Other innovations, such as the implementation of stacked quasioptical planar notch filters, allow for the diagnostic to be operated without interruption or degradation in performance during electron cyclotron resonance heating. Successful commissioning of the new diagnostic and a demonstration of the improved capabilities are presented in this paper, along with a discussion of the new technologies employed.
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Affiliation(s)
- B Tobias
- University of California at Davis, Davis, California 95616, USA
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46
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Smith DR, Kaye SM, Lee W, Mazzucato E, Park HK, Bell RE, Domier CW, Leblanc BP, Levinton FM, Luhmann NC, Menard JE, Yuh H. Observations of reduced electron Gyroscale fluctuations in national spherical torus experiment H-mode plasmas with large ExB flow shear. Phys Rev Lett 2009; 102:225005. [PMID: 19658873 DOI: 10.1103/physrevlett.102.225005] [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: 01/27/2009] [Indexed: 05/28/2023]
Abstract
Electron gyroscale fluctuation measurements in National Spherical Torus Experiment H-mode plasmas with large toroidal rotation reveal fluctuations consistent with electron temperature gradient (ETG) turbulence. Large toroidal rotation in National Spherical Torus Experiment plasmas with neutral beam injection generates ExB flow shear rates comparable to ETG linear growth rates. Enhanced fluctuations occur when the electron temperature gradient is marginally stable with respect to the ETG linear critical gradient. Fluctuation amplitudes decrease when the ExB flow shear rate exceeds ETG linear growth rates. The observations indicate that ExB flow shear can be an effective suppression mechanism for ETG turbulence.
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Affiliation(s)
- D R Smith
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
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Smith DR, Mazzucato E, Lee W, Park HK, Domier CW, Luhmann NC. A collective scattering system for measuring electron gyroscale fluctuations on the National Spherical Torus Experiment. Rev Sci Instrum 2008; 79:123501. [PMID: 19123561 DOI: 10.1063/1.3039415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A collective scattering system has been installed on the National Spherical Torus Experiment (NSTX) to measure electron gyroscale fluctuations in NSTX plasmas. The system measures fluctuations with k( perpendicular)rho(e) less, similar0.6 and k( perpendicular) less, similar20 cm(-1). Up to five distinct wavenumbers are measured simultaneously, and the large toroidal curvature of NSTX plasmas provides enhanced spatial localization. Steerable optics can position the scattering volume throughout the plasma from the magnetic axis to the outboard edge. Initial measurements indicate rich turbulent dynamics on the electron gyroscale. The system will be a valuable tool for investigating the connection between electron temperature gradient turbulence and electron thermal transport in NSTX plasmas.
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Affiliation(s)
- D R Smith
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA.
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48
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Zhang P, Domier CW, Liang T, Kong X, Tobias B, Shen Z, Luhmann NC, Park H, Classen IGJ, van de Pol MJ, Donné AJH, Jaspers R. The next generation of electron cyclotron emission imaging diagnostics (invited). Rev Sci Instrum 2008; 79:10F103. [PMID: 19044590 DOI: 10.1063/1.2967342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T(e) profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities far beyond what has been achieved to date. These include the development of a minilens array configuration with increased sensitivity antennas, a new local oscillator pumping scheme, enhanced electron cyclotron resonance heating shielding, and a highly flexible optical design with vertical zoom capability. Horizontal zoom and spot size (rf bandwidth) capabilities are also being developed with new ECEI electronics. An interface module is under development to remotely control all key features of the new ECEI instrument, many of which can be changed during a plasma discharge for maximum flexibility.
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Affiliation(s)
- P Zhang
- University of California at Davis, Davis, California 95616, USA
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49
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Lee W, Park HK, Cho MH, Namkung W, Smith DR, Domier CW, Luhmann NC. Spatial resolution study and power calibration of the high-k scattering system on NSTX. Rev Sci Instrum 2008; 79:10E723. [PMID: 19044540 DOI: 10.1063/1.2969404] [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: 05/27/2023]
Abstract
NSTX high-k scattering system has been extensively utilized in studying the microturbulence and coherent waves. An absolute calibration of the scattering system was performed employing a new millimeter-wave source and calibrated attenuators. One of the key parameters essential for the calibration of the multichannel scattering system is the interaction length. This interaction length is significantly different from the conventional one due to the curvature and magnetic shear effect.
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Affiliation(s)
- W Lee
- Department of Physics, POSTECH, Pohang 790-784, Republic of Korea.
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50
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Mazzucato E, Smith DR, Bell RE, Kaye SM, Hosea JC, LeBlanc BP, Wilson JR, Ryan PM, Domier CW, Luhmann NC, Yuh H, Lee W, Park H. Short-scale turbulent fluctuations driven by the electron-temperature gradient in the national spherical torus experiment. Phys Rev Lett 2008; 101:075001. [PMID: 18764544 DOI: 10.1103/physrevlett.101.075001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Indexed: 05/26/2023]
Abstract
Measurements with coherent scattering of electromagnetic waves in plasmas of the National Spherical Torus Experiment indicate the existence of turbulent fluctuations in the range of wave numbers k perpendicular rho(e)=0.1-0.4, corresponding to a turbulence scale length nearly equal to the collisionless skin depth. Experimental observations and agreement with numerical results from a linear gyrokinetic stability code support the conjecture that the observed turbulence is driven by the electron-temperature gradient.
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Affiliation(s)
- E Mazzucato
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.
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