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Title: Numerical and experimental study of atomic transport and Balmer line intensity in Linac4 negative ion source

Time structure of Balmer H{sub α} line intensity in Linac4 RF plasma has been analyzed by the combined simulation model of atomic transport and Collisional-Radiative models. As a preliminary result, time variation of the line intensity in the ignition phase of RF plasma is calculated and compared with the experimental results by photometry. For the comparison, spatial distribution of the local H{sub α} photon emission rate at each time is calculated from the numerical model. The contribution of the local photon emission rates to the observed line intensity via optical viewing port is also investigated by application of the mock-up of the optical viewing port and the known light source. It has been clarified from the analyses that the higher and the lower peaks of the H{sub α} line intensity observed during 1 RF cycle is mainly due to the different spatial distributions in the electron energy distribution function and the resultant local photon emission rate. These results support previous suggestion that the existence of the capacitive electric field in axial direction leads to the higher/lower peaks of the line intensity.
Authors:
; ;  [1] ; ;  [2]
  1. Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa, 223-8522 Japan (Japan)
  2. CERN, 1211 Geneva 23 (Switzerland)
Publication Date:
OSTI Identifier:
22391399
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; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANIONS; ATOM TRANSPORT; BALMER LINES; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; ELECTRIC FIELDS; ELECTRONS; ENERGY SPECTRA; ION SOURCES; LIGHT SOURCES; PHOTOMETRY; PHOTON EMISSION; PLASMA; PLASMA SIMULATION; SPATIAL DISTRIBUTION