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Freethy S, Figini L, Henderson M, El-Haroun H, Eliason B, Gibson S, Kirov K, Köhn-Seemann A, Konoplev I, Saarelma S, Sharma R, Speirs D, Vann R, Webster H, Wilson T. Microwave current drive for STEP and MAST Upgrade. EPJ WEB OF CONFERENCES 2023. [DOI: 10.1051/epjconf/202327704001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program has recently taken the decision to use exclusively microwave-based heating and current drive (HCD) actuators for its reactor concepts. This is based on a detailed assessment considering all viable HCD concepts, covering the grid to plasma efficiency, physics applications, technology maturity, integration, maintenance, and costs. Of the two microwave techniques: Electron Cyclotron (EC) and Electron Bernstein Wave (EBW), EC was deemed the lowest risk and EBW is retained as a potential path to a more efficient, higher performing device. To assess the ECCD efficiency, the GRAY beam tracing code was employed to perform detailed scans of the launcher position, toroidal and poloidal launch angle, and frequency over the first 3 cyclotron harmonics. For EBW, GENRAY/CQL3D were used to estimate the CD efficiency, demonstrating promising results. To reduce the physics uncertainties in present models for EBW coupling and current drive, MAST Upgrade will install two dual frequency (28, 34.8 GHz), 900kW, 5s gyrotrons from Kyoto Fusioneering, as part of the MAST Upgrade enhancements package. This will be accompanied by a flexible 2D steering launcher system to allow midplane coand counter-CD and above midplane launch for co-direction off-axis CD. Coupling efficiency is quantified by measuring the heating induced by reflected (i.e. non-coupled) power to a plate inserted in the reflected beam path. The experiments will also include EBW driven solenoid-free start-up, increasing power and pulse length by a factor of 10 compared to previous MAST experiments. This presentation will discuss the STEP microwave studies and the MAST Upgrade physics design and capabilities.
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Idei H, Fukuyama M, Sakai S, Mishra K, Nishimura K, Ikezoe R, Onchi T, Ido T, Hanada K. Adaptive Capon beamforming for lensless electron cyclotron emission imaging with high spatial resolution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103531. [PMID: 36319327 DOI: 10.1063/5.0101632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Electron cyclotron emission (ECE) imaging diagnostics incorporating a lensless approach have been developed for measurements involving active spatial selectivity and direction-of-arrival estimation. The Capon method for adaptive-array analysis was proposed to improve the spatial resolution of the two-dimensional ECE imaging technique. Broadband noise source emissions were used to simulate the ECE to verify the practical effectiveness of the Capon method in the ECE imaging. Multiple noise source emission positions were properly estimated with a high spatial resolution using the Capon method.
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Affiliation(s)
- H Idei
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8560, Japan
| | - M Fukuyama
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580, Japan
| | - S Sakai
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580, Japan
| | - K Mishra
- Institute for Plasma Research, Gandhinagar 382428, India
| | - K Nishimura
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan
| | - R Ikezoe
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8560, Japan
| | - T Onchi
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8560, Japan
| | - T Ido
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8560, Japan
| | - K Hanada
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8560, Japan
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Donnelly SM, Lopez NA, Dodin IY. Steepest-descent algorithm for simulating plasma-wave caustics via metaplectic geometrical optics. Phys Rev E 2021; 104:025304. [PMID: 34525672 DOI: 10.1103/physreve.104.025304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/20/2021] [Indexed: 11/06/2022]
Abstract
The design and optimization of radiofrequency-wave systems for fusion applications is often performed using ray-tracing codes, which rely on the geometrical-optics (GO) approximation. However, GO fails at wave cutoffs and caustics. To accurately model the wave behavior in these regions, more advanced and computationally expensive "full-wave" simulations are typically used, but this is not strictly necessary. A new generalized formulation called metaplectic geometrical optics (MGO) has been proposed that reinstates GO near caustics. The MGO framework yields an integral representation of the wavefield that must be evaluated numerically in general. We present an algorithm for computing these integrals using Gauss-Freud quadrature along the steepest-descent contours. Benchmarking is performed on the standard Airy problem, for which the exact solution is known analytically. The numerical MGO solution provided by the new algorithm agrees remarkably well with the exact solution and significantly improves on previously derived analytical approximations of the MGO integral.
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Affiliation(s)
- Sean M Donnelly
- Department of Physics & Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Nicolas A Lopez
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA
| | - I Y Dodin
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA.,Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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Instability of Electron Bernstein Mode in Presence of Drift Wave Turbulence Associated with Density and Temperature Gradients. JOURNAL OF FUSION ENERGY 2020. [DOI: 10.1007/s10894-020-00269-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Seltzman A, Anderson J, Forest C. Construction of an EBW Heating System for the MST RFP. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201920302010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The first observation of rf heating in a reversed field pinch (RFP) using the electron Bernstein wave (EBW) has been demonstrated on Madison Symmetric Torus (MST). The design of the RF heating system used in this experiment is described. Klystron and antenna limitations are examined during launch into the plasma.
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Seltzman AH, Anderson JK, Diem SJ, Goetz JA, Forest CB. Observation of Electron Bernstein Wave Heating in a Reversed Field Pinch. PHYSICAL REVIEW LETTERS 2017; 119:185001. [PMID: 29219560 DOI: 10.1103/physrevlett.119.185001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Indexed: 06/07/2023]
Abstract
The first observation of rf heating in a reversed field pinch (RFP) using the electron Bernstein wave (EBW) is demonstrated on the Madison Symmetric Torus. Propagation across and heating in a stochastic magnetic field is observed. Novel techniques are required to measure the suprathermal electron tail generated by EBW heating in the presence of intense Ohmic heating. rf-heated electrons directly probe the edge transport properties in the RFP; measured loss rates imply a large noncollisional radial diffusivity.
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Affiliation(s)
- A H Seltzman
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J K Anderson
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S J Diem
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J A Goetz
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C B Forest
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Shevchenko V, Cunningham G, Gurchenko A, Gusakov E, Lloyd B, O’Brien M, Saveliev A, Surkov A, Volpe F, Walsh M. Development of Electron Bernstein Wave Research in MAST. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst07-a1499] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- V. Shevchenko
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - G. Cunningham
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - A. Gurchenko
- Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - E. Gusakov
- Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - B. Lloyd
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - M. O’Brien
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - A. Saveliev
- Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - A. Surkov
- Ioffe Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - F. Volpe
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - M. Walsh
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
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Zohm H. Recent Experimental Progress in Electron Cyclotron Resonance Heating and Electron Cyclotron Current Drive in Magnetically Confined Fusion Plasmas. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst07-a1492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hartmut Zohm
- Max-Planck-Institut für Plasmaphysik, EURATOM Association D-85748 Garching, Germany
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Yoshimura Y, Ferrando-Margalet S, Isobe M, Suzuki C, Shimizu A, Akiyama T, Takahashi C, Nagaoka K, Nishimura S, Minami T, Matsuoka K, Okamura S, Igami H, Kubo S, Shimozuma T, Notake T, Mutoh T, Nagasaki K. Experimental Observations of O-X-B Heating of Overdense Plasmas in CHS. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst07-a1500] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Y. Yoshimura
- National Institute for Fusion Science, Toki 509-5292, Japan
| | | | - M. Isobe
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - C. Suzuki
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - A. Shimizu
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Akiyama
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - C. Takahashi
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Nagaoka
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Nishimura
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Minami
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Matsuoka
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Okamura
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - H. Igami
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Kubo
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Shimozuma
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Notake
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Mutoh
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Nagasaki
- Kyoto University, Institute of Advanced Energy, Uji 611-0011, Japan
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Castejón F, Tereshchenko MA, Sarksyan KA, Fernández Á, Cappa Á, Batanov GM, Sakharov AS, Martín R. Electron Bernstein Wave Heating Calculations for TJ-II Plasmas. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst04-a571] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | | | - Karen A. Sarksyan
- Russian Academy of Sciences, General Physics Institute, Moscow, Russia
| | | | - Álvaro Cappa
- Asociación EURATOM-CIEMAT para Fusión 28040 Madrid, Spain
| | - G. M. Batanov
- Russian Academy of Sciences, General Physics Institute, Moscow, Russia
| | - A. S. Sakharov
- Russian Academy of Sciences, General Physics Institute, Moscow, Russia
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Klinger T, Baylard C, Beidler C, Boscary J, Bosch H, Dinklage A, Hartmann D, Helander P, Maßberg H, Peacock A, Pedersen T, Rummel T, Schauer F, Wegener L, Wolf R. Towards assembly completion and preparation of experimental campaigns of Wendelstein 7-X in the perspective of a path to a stellarator fusion power plant. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2013.02.153] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Shiraiwa S, Hanada K, Hasegawa M, Idei H, Kasahara H, Mitarai O, Nakamura K, Nishino N, Nozato H, Sakamoto M, Sasaki K, Sato K, Takase Y, Yamada T, Zushi H. Heating by an electron Bernstein wave in a spherical tokamak plasma via mode conversion. PHYSICAL REVIEW LETTERS 2006; 96:185003. [PMID: 16712369 DOI: 10.1103/physrevlett.96.185003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Indexed: 05/09/2023]
Abstract
The first successful high power heating of a high dielectric constant spherical tokamak plasma by an electron Bernstein wave (EBW) is reported. An EBW was excited by mode conversion (MC) of an mode cyclotron wave injected from the low magnetic field side of the TST-2 spherical tokamak. Evidence of electron heating was observed as increases in the stored energy and soft x-ray emission. The increased emission was concentrated in the plasma core region. A heating efficiency of over 50% was achieved, when the density gradient in the MC region was sufficiently steep.
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Affiliation(s)
- S Shiraiwa
- Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561, Japan.
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