title: Characteristics of plasma grid bias in large-scaled negative ion source.
abstract: The electron density was measured at various bias voltages to understand how the plasma grid bias affects the electron near the plasma grid in large-scaled negative ion sources. It was found that the response of the electron to the bias voltage changes depending on negative ion production processes. The electron density remarkably decreases with increasing the bias voltage in the pure-volume plasma. On the other hand, the electron density depends on the bias voltage weakly in the Cs-seeded plasma. In addition, it was observed that the response of the co-extracted electron current to the bias voltage has similar trend to that of the electron density.
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kisaki
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tsumori
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakano
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Osakabe
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nagaoka
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takeiri
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Kaneko