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Title: Balmer-α spectrum measurements of the LHD one-third ion source

Wavelength spectra of Balmer-α light from plasmas in the extraction region of the Large Helical Device-R&D negative ion source, or the LHD one-third ion source have exhibited a blue shift as a negative bias voltage was applied to the plasma grid. The blue shift increased as the negative bias voltage with respect to the local plasma potential was increased. The measured spectra were compared with the velocity distributions of surface reflected hydrogen atoms calculated by atomic collisions in amorphous target code. The arc power and the source H{sub 2} pressure also affected the shift and broadening in the observed Balmer-α spectra. The possibility of identifying the negative hydrogen ions produced at the low work function plasma grid surface by high resolution spectroscopy is discussed.
Authors:
 [1] ;  [2] ; ; ;  [3] ;  [4]
  1. Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)
  2. School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)
  3. National Institute for Fusion Science, Toki, Gifu 509-5202 (Japan)
  4. Graduate School of Frontier Science, The University of Tokyo, Kashiwa, 277-8561 Chiba (Japan)
Publication Date:
OSTI Identifier:
22482929
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATOM COLLISIONS; GRIDS; HYDROGEN; HYDROGEN IONS; ION SOURCES; LHD DEVICE; PLASMA; PLASMA POTENTIAL; SPECTRA; SPECTROSCOPY