Influence of H- velocity on H- extraction probability from a negative ion source.
We investigate influence of H(-) initial transport direction and kinetic energy on H(-) extraction probability with three-dimensional Monte Carlo calculation. As a result, lower energy H(-) ions are strongly trapped by the electrical potential structure, so that initial condition of H(-) transport direction is cancelled by alignment of the electric field; thus, it has lower influence for H(-) extraction probability. Besides, the potential hill induced by the beam extraction voltage more effectively enhances H(-) extraction probability for the lower energy H(-) ions. The correlation between the magnitude of the local plasma potential near the extraction region and the mean velocity of H(-) ions in the region should determine the H(-) extraction probability from the ion source.
Matsumoto
Y
Y
Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan. ymatsumoto@tokushima.bunri-u.ac.jp
Nishiura
M
M
Shinto
K
K
Yamaoka
H
H
Sasao
M
M
Wada
M
M