Response of negative ion beamlet width and axis deflection to RF field in beam extraction region

Abstract Beam-divergence characteristics of single negative ion beamlet have been experimentally investigated with a superimposition of a controlled perturbation of a radio frequency wave (RF) field in a filament-arc discharge negative ion source. Oscillations of a negative-ion beamlet width and axi...

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Bibliographic Details
Main Authors: Kenichi Nagaoka, Haruhisa Nakano, Taiga Hamajima, Ryoya Nakamoto, Katsuyoshi Tsumori, Masaki Osakabe, Masashi Kisaki, Kenji Miyamoto, Kazunori Takahashi, Ursel Fantz
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-024-81334-w
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Summary:Abstract Beam-divergence characteristics of single negative ion beamlet have been experimentally investigated with a superimposition of a controlled perturbation of a radio frequency wave (RF) field in a filament-arc discharge negative ion source. Oscillations of a negative-ion beamlet width and axis responding to the RF perturbation were observed, which may be a cause of the larger beam divergence angle of the RF negative ion source for ITER. It is pointed out that the oscillation of the beamlet width depends on the perveance and on an RF frequency such that the oscillation is suppressed at perveance-matched conditions and at low RF frequency.
ISSN:2045-2322