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Contribution Poster

H– and D– sources for fusion, accelerators and other applications

Observation of low frequency oscillation in a filament-arc-based negative ion source

Speakers

  • Dr. Kenichi NAGAOKA

Primary authors

Co-authors

Content

Development of high-density negative ion plasmas and control of behaviors of the negative ion plasmas and beams are performed for a variety of application of negative ion beams. Three negative ion beam injectors based on filament-arc source have been operational for plasma experiment in Large Helical Device. In order to improve the negative ion beam performance in deuterium beam operation, further investigation of particle dynamics and beam characteristics in the negative ion source are experimentally performed in NIFS-NBTS.

Recently, an oscillation with the frequency of several hundred Hz was observed in the plasma. The oscillation seems to be driven by a power supply for biasing plasma grid, and should be suppressed for working injector. In this study, however, the oscillation is useful to investigate the dynamic response of the beam to the plasma in the vicinity of the plasma grid.

In the symposium, the observed oscillation of the plasma will be presented, and the response of the beam characteristics will be discussed.