Analysis of electron temperature distribution by kinetic modeling of electron energy distribution function in JAEA 10 ampere negative ion source

T. Shibata, R. Terasaki, M. Kashiwagi, T. Inoue, M. Dairaku, M. Taniguchi, H. Tobari, N. Umeda, K. Watanabe, K. Sakamto, A. Hatayama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Citations (Scopus)

Abstract

In large negative ion sources of the neutral beam injector (NBI) for large fusion devices, such as ITER and JT-60SA, one of issues is that negative ion beam might be partially intercepted at acceleration grids due to a spatial non-uniformity of negative ion production on large extraction area. Previous experiments have shown that fast electrons emitted from filament cathodes are transported in a longitudinal direction by B × grad B drift and the spatial distribution of electron temperature (Te) is strongly related with the non-uniformity of negative ion production. In this study, a three-dimensional electron transport analysis code including detailed collision processes has been developed to clarify a physical mechanism of non-uniform Te distribution. Electron density and temperature in the analysis agree well with measurements by Langmuir probe in the JAEA 10A ion source. Then, this study has clarified that the non-uniformity of Te distribution is mainly caused by the following reasons; i) fast electrons drifted in the longitudinal direction survive near the end wall with high energy up to E = 25 - 60 eV and ii) they produce thermal electrons by collision with plasma particles there.

Original languageEnglish
Title of host publicationThird International Symposium on Negative Ions, Beams and Sources, NIBS 2012
Pages177-186
Number of pages10
DOIs
Publication statusPublished - 2013 Apr 12
Event3rd International Symposium on Negative Ions, Beams and Sources, NIBS 2012 - Jyvaskyla, Finland
Duration: 2012 Sep 32012 Sep 7

Publication series

NameAIP Conference Proceedings
Volume1515
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other3rd International Symposium on Negative Ions, Beams and Sources, NIBS 2012
CountryFinland
CityJyvaskyla
Period12/9/312/9/7

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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