1. Response of H− ions to extraction field in a negative hydrogen ion source
- Author
-
M. Shibuya, Katsuyoshi Tsumori, K. Nagaoka, Yasuhiko Takeiri, Haruhisa Nakano, Katsunori Ikeda, Masashi Kisaki, Masaki Osakabe, and S. Geng
- Subjects
010302 applied physics ,Materials science ,Mechanical Engineering ,Extraction (chemistry) ,Plasma ,Stagnation point ,01 natural sciences ,Neutral beam injection ,010305 fluids & plasmas ,Ion ,symbols.namesake ,Ion beam deposition ,Nuclear Energy and Engineering ,Physics::Plasma Physics ,Physics::Space Physics ,0103 physical sciences ,symbols ,Langmuir probe ,General Materials Science ,Atomic physics ,Beam (structure) ,Civil and Structural Engineering - Abstract
In order to investigated the dynamics of H− ions and understand the extraction process inside filament-arc-driven plasmas in a Cs-seeded negative ion source, diagnostic experiments using a directional Langmuir probe combined with photodetachment measurement have been conducted. Two-dimensional flow pattern of H− ion flow has been obtained as well as the profile of H− ion density. The result shows that H− ions come from the direction of plasma grid surface, flow to the plasma in the extraction region. During beam extraction, H− ion flow turns to the beam direction. The stagnation point of H− ion flow is at ∼20 mm apart from the plasma grid. Around the stagnation point, the maximum decrement of H− density caused by beam extraction appears. The results indicate that H− ions are extracted from the plasma volume. The extraction process occurs in a region near the plasma grid aperture with boundary of ∼20 mm apart from the plasma gird.
- Published
- 2017