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Nonuniform plasma meniscus modelling based on backward calculation of negative ion beamlet

Author
Abstract

The shape of a plasma meniscus is a key factor to determine the beam focusing. The physics model of the meniscus formation for hydrogen negative ion sources has not been established yet. A backward trajectory calculation based on experimental observation is performed in order to derive the particle information at the meniscus. It is observed that the negative ion density is spatially nonuniform in the direction parallel to the magnets for suppression of co-extracted electrons. A nonuniformity of the negative ion density in the vicinity of the meniscus is taken into account in the forward trajectory calculation. It reveals that the nonuniform negative ion distribution leads to degradation of the beam focusing and the beam splitting in phase space. The importance of the spatial distribution of negative ions on meniscus modelling is discussed with a comparison to uniform extraction model.

Year of Publication
2022
Journal
Nuclear Fusion
Volume
62
Issue
10
Number of Pages
106031
Publisher
IOP Publishing
DOI
10.1088/1741-4326/ac8604
PId
70a705bdf296ed594e130c826fa0191b
Alternate Journal
Nucl. Fusion
Label
OA
Journal Article
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