title: Influence of the electron cross-field diffusion in negative ion sources with the transverse magnetic field and the plasma-electrode bias.
abstract: The physical mechanisms involved in the extraction of H(-) ions from the negative ion source are studied with a PIC 2D3V code. The effect of a weak magnetic field transverse to the extraction direction is taken into account, along with a variable bias voltage applied on the plasma electrode (PE). In addition to previous modeling works, the electron diffusion across the magnetic field is taken into account as a simple one-dimensional random-walk process. The results show that without PE bias, the value of the diffusion coefficient has a significant influence upon the value of the extracted H(-) current. However, the value of this coefficient does not affect qualitatively the mechanism leading to the peak of extracted H(-) ion current observed for an optimum value of the PE bias.
authors.affiliation: Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kuppel
authors.forename: D
authors.initials: D
authors.lastname: Matsushita
authors.forename: A
authors.initials: A
authors.lastname: Hatayama
authors.forename: M
authors.initials: M
authors.lastname: Bacal