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Title: Evaluation of negative ion distribution changes by image processing diagnostic

Distributions of hydrogen Balmer-α (H{sub α}) intensity and its reduction behavior close to a plasma grid (PG) surface have been observed by a spectrally selective imaging system in an arc discharge type negative hydrogen ion source in National Institute for Fusion Science. H{sub α} reduction indicates a reduction of negative hydrogen ions because the mutual neutralization process between H{sup +} and H{sup −} ions causes the dominant excitation process for H{sub α} emission in the rich H{sup −} condition such as in ionic plasma. We observed a significant change in H{sub α} reduction distribution due to change in the bias voltage, which is used to suppress the electron influx. Small H{sub α} reduction in higher bias is likely because the production of negative ions is suppressed by the potential difference between the plasma and PG surface.
Authors:
; ; ; ; ; ; ; ;  [1] ;  [2]
  1. National Institute for Fusion Science, 322-6 Oroshi Toki Gifu, 509-5292 (Japan)
  2. The Graduate University for Advanced Studies, Toki Gifu, 509-5292 (Japan)
Publication Date:
OSTI Identifier:
22391428
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 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; ELECTRIC ARCS; ELECTRIC POTENTIAL; ELECTRONS; EXCITATION; HYDROGEN; HYDROGEN IONS 1 MINUS; HYDROGEN IONS 1 PLUS; IMAGE PROCESSING; PHOTON EMISSION; PLASMA; POTENTIALS; REDUCTION; SURFACES