Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources

S. Kuppel, D. Matsushita, Akiyoshi Hatayama, M. Bacal

研究成果: Article

32 引用 (Scopus)

抄録

This numerical study focuses on the physical mechanisms involved in the extraction of volume-produced H? ions from a steady state laboratory negative hydrogen ion source with one opening in the plasma electrode (PE) on which a dc-bias voltage is applied. A weak magnetic field is applied in the source plasma transversely to the extracted beam. The goal is to highlight the combined effects of the weak magnetic field and the PE bias voltage (upon the extraction process of H? ions and electrons). To do so, we focus on the behavior of electrons and volume-produced negative ions within a two-dimensional model using the particle-in-cell method. No collision processes are taken into account, except for electron diffusion across the magnetic field using a simple random-walk model at each time step of the simulation. The results show first that applying the magnetic field (without PE bias) enhances H? ion extraction, while it drastically decreases the extracted electron current. Secondly, the extracted H? ion current has a maximum when the PE bias is equal to the plasma potential, while the extracted electron current is significantly reduced by applying the PE bias. The underlying mechanism leading to the above results is the gradual opening by the PE bias of the equipotential lines towards the parts of the extraction region facing the PE. The shape of these lines is due originally to the electron trapping by the magnetic field.

元の言語English
記事番号013305
ジャーナルJournal of Applied Physics
109
発行部数1
DOI
出版物ステータスPublished - 2011 1 1

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plasma electrodes
hydrogen ions
negative ions
ion sources
numerical analysis
magnetic fields
electrons
ion extraction
equipotentials
electron diffusion
plasma potentials
electric potential
two dimensional models
random walk
ion currents
ions
trapping
collisions
cells

ASJC Scopus subject areas

  • Physics and Astronomy(all)

これを引用

Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources. / Kuppel, S.; Matsushita, D.; Hatayama, Akiyoshi; Bacal, M.

:: Journal of Applied Physics, 巻 109, 番号 1, 013305, 01.01.2011.

研究成果: Article

Kuppel, S. ; Matsushita, D. ; Hatayama, Akiyoshi ; Bacal, M. / Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources. :: Journal of Applied Physics. 2011 ; 巻 109, 番号 1.
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