Optical measurement of Cs distribution in the large negative ion source.
To investigate a Cs behavior, optical diagnostic tools have been installed in the large negative ion source, an arc discharge used at large helical device neutral beam injector. A large Cs sputtering is observed during beam extraction due to the backstreaming H(+) ions. Distribution of Cs(+) light is uniform in the case of a balanced arc discharge, but large increase of Cs(+) light during beam extraction is observed in a nonuniform arc discharge. Controlling of the discharge uniformity is effective to reduce the local heat loading from the backstreaming H(+) ions at the backplate of ion source.
Ikeda
K
K
National Institute for Fusion Science, Toki, Gifu, Japan.
Nagaoka
K
K
Takeiri
Y
Y
Fantz
U
U
Kaneko
O
O
Osakabe
M
M
Oka
Y
Y
Tsumori
K
K