Plasma and Fusion Research

Volume 18, 1401008 (2023)

Regular Articles


Effect of Surface Produced H Ion on the Plasma Meniscus in Negative Hydrogen Ion Sources
Katsuya HAYASHI, Kazuo HOSHINO, Akiyoshi HATAYAMA, Kenji MIYAMOTO1) and Jacques LETTRY2)
Keio University, Kanagawa 223-8522, Japan
1)
Naruto University of Education, Tokushima 772-8502, Japan
2)
CERN Rte de Meyrin, 1200 Geneva, Switzerland
(Received 18 July 2022 / Accepted 14 November 2022 / Published 3 March 2023)

Abstract

To extract intense ion beams with good beam optics from ion sources, controlling the distance deff between the plasma meniscus (i.e., beam emission surface) and the beam extraction grid is important. This study conducts a novel investigation into the dependence of the effective distance deff on the amount of surface H production SH. For this purpose, a 3D PIC (three dimensional Particle-in-Cell) simulation is conducted to obtain a model geometry of the extraction region for a H ion source with SH as a parameter. Based on results, deff significantly depends on SH and the H-electron density ratio (α = nH/ne) in front of the extraction aperture for the same plasma density; as SH increases, deff decreases. The results suggest that SH is critical for controlling deff and the resultant beam optics extracted from the negative ion source.


Keywords

negative ion source, particle-in-cell, plasma meniscus, surface-produced ion

DOI: 10.1585/pfr.18.1401008


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