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Title: Electron Bernstein wave heating and emission measurement through the very narrow O-X-B mode conversion window in the LHD

In the large helical device (LHD), the theoretically predicted width of the ordinary-extraordinary-electron Bernstein wave (O-X-B) mode conversion (MC) window is comparable to the beam width and the power deposition is located in the off-axis region if the 77GHz fundamental electron cyclotron (EC) wave of is launched from an existing horizontal port antenna. In the experiment, the actual MC window location was looked for with changing the aiming. The effective aiming with that the increase of the stored energy was observed was two degrees apart from the location of the theoretical MC window at a maximum. Measurement of the waves originated from the thermally emitted EBW and radiated via the B-X-O mode conversion process is effective to improve the accuracy of the theoretical prediction with comparison between the theoretical and the experimental results. The theoretical prediction suggests that the width of the MC window of the fundamental 77GHz EC wave can be expanded if the lower port antenna is used. On the other hand, the MC window of the second harmonic 154GHz EC wave is blocked by horizontal port wall if another horizontal port antenna is used. It is required to move the final mirror of the quasi-optical antenna towardmore » the plasma surface. Focusing of the beam at the plasma cutoff is (PC) also necessary for the effective mode conversion.« less
Authors:
; ; ; ; ; ; ;  [1] ;  [2] ; ;  [3] ;  [4] ;  [5]
  1. National Institute for Fusion Science, Toki (Japan)
  2. National Institute for Fusion Science, Toki, Japan and Department of Energy Engineering and Science, Nagoya Univ., Nagoya (Japan)
  3. Department of Energy Engineering and Science, Nagoya Univ., Nagoya (Japan)
  4. Research Institute for Applied Mechanics, Kyusyu Univ., Kasuga (Japan)
  5. Institute of Advanced Energy, Kyoto Univ., Uji (Japan)
Publication Date:
OSTI Identifier:
22263894
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1580; Journal Issue: 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; BERNSTEIN MODE; DEPOSITION; ELECTRONS; EMISSION; FORECASTING; LHD DEVICE; MODE CONVERSION; PLASMA WAVES; STORED ENERGY