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Jiang M, Zhu Y, Yu X, Shi Z, Luhmann N, Yang Z, Deng W, Yang Z, Zhou Y, Tong R. Optical design and synthetic analysis of the electron cyclotron emission imaging diagnostic of HL-2M tokamak. FUSION ENGINEERING AND DESIGN 2023. [DOI: 10.1016/j.fusengdes.2023.113570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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2
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Zhu Y, Chen Y, Yu JH, Domier C, Yu G, Liu X, Kramer G, Ren Y, Diallo A, Luhmann NC, Li X. System-on-chip approach microwave imaging reflectometer on DIII-D tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113509. [PMID: 36461457 DOI: 10.1063/5.0099170] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 09/08/2022] [Indexed: 06/17/2023]
Abstract
System-on-chip millimeter wave integrated circuit technology is used on the two-dimensional millimeter-wave imaging reflectometer (MIR) upgrade for density fluctuation imaging on the DIII-D tokamak fusion plasma. Customized CMOS chips have been successfully developed for the transmitter module and receiver module array, covering the 55-75 GHz working band. The transmitter module has the capability of simultaneously launching eight tunable probe frequencies (>0 dBm output power each). The receiver enclosure contains 12 receiver modules in two vertical lines. The quasi-optical local oscillator coupling of previous MIR systems has been replaced with an internal active frequency multiplier chain for improved local oscillator power delivery and flexible installation in a narrow space together with improved shielding against electromagnetic interference. The 55-75 GHz low noise amplifier, used between the receiver antenna and the first-stage mixer, significantly improves module sensitivity and suppresses electronics noise. The receiver module has a 20 dB gain improvement compared with the mini-lens approach and better than -75 dBm sensitivity, and its electronics noise temperature has been reduced from 55 000 K down to 11 200 K. The V-band MIR system is developed for co-located multi-field investigation of MHD-scale fluctuations in the pedestal region with W-band electron cyclotron emission imaging on DIII-D tokamak.
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Affiliation(s)
- Y Zhu
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - Y Chen
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - J-H Yu
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - C Domier
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - G Yu
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - X Liu
- Department of Electrical and Computer Engineering, 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
| | - N C Luhmann
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
| | - X Li
- Department of Electrical and Computer Engineering, University of California Davis, Davis, California 95616, USA
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Sabot R, Giacalone JC, Nam Y, Berne A, Brun C, Elbèze D, Faisse F, Gargiulo L, Kim M, Lee W, Lotte P, Park HK, Santraine B, Yun G. Development of Microwave Imaging Diagnostics for WEST Tokamak. JOURNAL OF FUSION ENERGY 2019. [DOI: 10.1007/s10894-019-00216-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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4
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Sabot R, Nam Y, Brun C, Elbèze D, Faisse F, Gargiulo L, Kim M, Lee W, Lotte P, Park HK, Yun G. Integration of an Electron Cyclotron Imaging diagnostic system on the WEST tokamak. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201920303011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An Electron Cyclotron Emission Imaging (ECEI) diagnostic system for the WEST tokamak has been developed under the UNIST-WEST collaboration. This diagnostic system is designed to overcome accessibility and thermomechanical constraints for long pulse operation. The first O-mode channel will be installed in the first trimester of 2019 to probe the low field side (LFS) of the WEST plasma. Two large metallic reflective mirrors are installed inside the duct which is being used for maintenance access. They are suspended on a rail to facilitate mirror manipulation. The ex-vessel optical system (lens, detection array, etc.) is housed in a compact optical enclosure that fits in a tight free space between the port flange and tokamak access lobby. The design emphasized reproducibility of the precise alignment between in-vessel mirrors and optical enclosure since the both elements must be removed during shutdown period for maintenance access. The overall optical system was fully tested at UNIST last year. The test results demonstrated that the imaging optics can full access at any radial position on the LFS. The 2D beam pattern measurements were consistent with the design values.
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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. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10H120. [PMID: 30399858 DOI: 10.1063/1.5035373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [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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6
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Nagayama Y, Ito N, Kuwahara D, Tsuchiya H, Yamaguchi S. Development of 2-D horn-antenna millimeter-wave imaging device (HMID) for the plasma diagnostics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:044703. [PMID: 28456234 DOI: 10.1063/1.4980150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The two-dimensional (2-D) Horn-antenna Millimeter-wave Imaging Device (HMID) has been developed for the O-mode Microwave Imaging Reflectometry (O-MIR) in the Large Helical Device (LHD). The detectable frequency range of the HMID is 23-33 GHz, which corresponds to the cutoff electron density of 0.8-1.5 × 1019 m-3 in the O-MIR. The HMID is a 2-D imaging device that improves on the horn-antenna mixer array, which had been developed for the X-mode MIR in the LHD. In the HMID, the signal (RF) wave from the horn antenna is transmitted to the microstrip line by the finline transmitter, and this is mixed by the double-balanced-mixer with the local oscillation wave that is fed by a coaxial cable. By using the HMID, the MIR optical system can be significantly simplified.
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Affiliation(s)
- Y Nagayama
- National Institute for Fusion Science, National Institute for Natural Sciences, Toki 509-5292, Japan
| | - N Ito
- National Institute of Technology, Ube College, Ube 755-8555, Japan
| | - D Kuwahara
- Tokyo University of Agriculture and Technology, Koganei 184-8588, Japan
| | - H Tsuchiya
- National Institute for Fusion Science, National Institute for Natural Sciences, Toki 509-5292, Japan
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Choi MJ, Park HK, Yun GS, Nam YB, Choe GH, Lee W, Jardin S. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:013506. [PMID: 26827320 DOI: 10.1063/1.4940030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/05/2016] [Indexed: 06/05/2023]
Abstract
The electron cyclotron emission imaging (ECEI) instrument is widely used to study the local electron temperature (Te) fluctuations by measuring the ECE intensity IECE ∝ Te in tokamak plasmas. The ECEI measurement is often processed in a normalized fluctuation quantity against the time averaged value due to complication in absolute calibration. In this paper, the ECEI channels are relatively calibrated using the flat Te assumption of the sawtooth crash or the tearing mode island and a proper extrapolation. The 2-D relatively calibrated electron temperature (Te,rel) images are reconstructed and the displacement amplitude of the magnetohydrodynamic modes can be measured for the accurate quantitative growth analysis.
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Affiliation(s)
- M J Choi
- National Fusion Research Institute, Daejeon 34133, South Korea
| | - H K Park
- National Fusion Research Institute, Daejeon 34133, South Korea
| | - G S Yun
- Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Y B Nam
- Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - G H Choe
- Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - W Lee
- Ulsan National Institute of Science and Technology, Ulsan 689-798, South Korea
| | - S Jardin
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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8
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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. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D820. [PMID: 25430233 DOI: 10.1063/1.4890401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A 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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9
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Liu JX, Milbourne T, Bitter M, Delgado-Aparicio L, Dominguez A, Efthimion PC, Hill KW, Kramer GJ, Kung C, Kubota S, Kasparek W, Lu J, Pablant NA, Park H, Tobias B. Alternative optical concept for electron cyclotron emission imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D802. [PMID: 25430215 DOI: 10.1063/1.4884902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.
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Affiliation(s)
- J X Liu
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
| | - T Milbourne
- Department of Physics, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - M Bitter
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | | | - A Dominguez
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - P C Efthimion
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - K W Hill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - G J Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - C Kung
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - S Kubota
- Department of Physics, University of California Los Angeles, Los Angeles, California 90095, USA
| | - W Kasparek
- Department of Electrical Engineering, University of Stuttgart, Stuttgart, Germany
| | - J Lu
- Department of Physics, Chongqing University, Chongqing 400044, China
| | - N A Pablant
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - H Park
- Ulsan National Institute of Science and Technology, Ulsan 689-798, South Korea
| | - B Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
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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. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D833. [PMID: 25430246 DOI: 10.1063/1.4891061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [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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11
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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. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:063505. [PMID: 24985817 DOI: 10.1063/1.4883180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [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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Wang Z, Lin Z, Holod I, Heidbrink WW, Tobias B, Van Zeeland M, Austin ME. Radial localization of toroidicity-induced Alfvén eigenmodes. PHYSICAL REVIEW LETTERS 2013; 111:145003. [PMID: 24138247 DOI: 10.1103/physrevlett.111.145003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Indexed: 06/02/2023]
Abstract
Linear gyrokinetic simulation of fusion plasmas finds a radial localization of the toroidal Alfvén eigenmodes (TAEs) due to the nonperturbative energetic particle (EP) contribution. The EP-driven TAE has a radial mode width much smaller than that predicted by the magnetohydrodynamic theory. The TAE radial position stays around the strongest EP pressure gradients when the EP profile evolves. The nonperturbative EP contribution is also the main cause for the breaking of the radial symmetry of the ballooning mode structure and for the dependence of the TAE frequency on the toroidal mode number. These phenomena are beyond the picture of the conventional magnetohydrodynamic theory.
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Affiliation(s)
- Zhixuan Wang
- University of California, Irvine, California 92697, USA
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13
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Yun G, Lee W, Choi M, Lee J, Choe G, Park H, Domier C, Luhmann N, Donné AJH, Lee J, Park S, Joung M, Bae Y, Jeon Y, Yoon S. Visualization of core and edge MHD instabilities in 2D using ECEI. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123203002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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14
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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. PHYSICAL REVIEW LETTERS 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] [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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