Plasma and Fusion Research
Volume 13, 1205110 (2018)
Rapid Communications
- 1)
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
- 2)
- SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292, Japan
- 3)
- Graduate School of Science, Nagoya University, Nagoya 464-8601, Japan
Abstract
Plasma grid bias has been utilized for reducing an electron density in the vicinity of a plasma grid in negative ion sources for fusion, resulting in achievement of low co-extracted electron current. In this study, the effectiveness and feasibility of the plasma grid bias on beam optics optimization are demonstrated. It is shown that the beam optics strongly depends on the bias voltage and is successfully optimized at different bias voltages depending on the discharge power. Responses of the beam properties such as the perveance and the current ratio to the plasma grid bias are also shown for both hydrogen and deuterium beams.
Keywords
hydrogen negative ion source, beam optics, meniscus, perveance, plasma grid bias
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