title: Analysis of the H- ion emissive surface in the extraction region of negative ion sources.
abstract: To understand the plasma characteristics in the extraction region of negative H(-) sources is very important for the optimization of H(-) extraction from the sources. The profile of plasma density and electrostatic potential in the extraction region with and without extraction grid voltage are analyzed with a 2D particle in cell modeling of the NIFS-RD H(-) sources. The simulation results make clear the physical process forming a double ion plasma layer (which consists only of positive H(+) and negative H(-) ions) recently observed in the Cs-seeded experiments of the NIFS-R&D source in the vicinity of the extraction hole and the plasma grid. The results also give a useful insight into the formation mechanism of the plasma meniscus and the H(-) extraction process for such double ion plasma.
authors.affiliation: Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kameyama
authors.forename: T
authors.initials: T
authors.lastname: Fukuyama
authors.forename: S
authors.initials: S
authors.lastname: Wada
authors.forename: S
authors.initials: S
authors.lastname: Kuppel
authors.forename: K
authors.initials: K
authors.lastname: Tsumori
authors.forename: H
authors.initials: H
authors.lastname: Nakano
authors.forename: A
authors.initials: A
authors.lastname: Hatayama
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: A
authors.initials: A
authors.lastname: Fukano
authors.forename: M
authors.initials: M
authors.lastname: Bacal