skip to main content

SciTech ConnectSciTech Connect

Title: Numerical study of atomic production rate in hydrogen negative ion sources with the effect of non-equilibrium electron energy distribution function

Spatial non-uniformity of the dissociative hydrogen atom (H{sup 0}) production has been investigated in a large negative ion source (JAEA 10 A source) with the electron energy distribution function (EEDF) obtained by a Monte-Carlo simulation code for electron transport in 3D3V (three dimensional real and velocity) space. It has been shown that the H{sup 0} production rate becomes larger in the upper region (one side in the longitudinal direction) of the source chamber. This spatial non-uniformity of the H{sup 0} production profile is mainly explained by the non-equilibrium features of the EEDF in the upper region, i.e., the EEDF consists of thermal electron component with kinetic energy ε < 25 eV and fast electron component with energy ε > 25 eV in the upper region, while the EEDF mainly consists of only thermal electrons in the bottom region. These characteristics for the EEDF and the energy dependence of cross-sections for dissociation and dissociative ionization processes lead to the non-uniform profile of the H{sup 0} production. The above numerical results of the spatial H{sup 0} non-uniformity are validated and confirmed by comparisons with those by spectroscopic measurement. It has been clarified that the non-equilibrium (fast electron) component of the EEDF hasmore » a large contribution to the non-uniformity of the H{sup 0} production rate.« less
Authors:
;  [1] ; ; ;  [2]
  1. Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan)
  2. Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 311-0193 (Japan)
Publication Date:
OSTI Identifier:
22217933
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 14; Other Information: (c) 2013 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; ANIONS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; CROSS SECTIONS; ELECTRONS; ENERGY DEPENDENCE; ENERGY SPECTRA; EQUILIBRIUM; EV RANGE; FUNCTIONS; HYDROGEN; ION SOURCES; JAEA; KINETIC ENERGY; LEAD; MONTE CARLO METHOD; NUMERICAL ANALYSIS; TRANSPORT THEORY; USA