Effects of filament geometry on the arc efficiency of a high-intensity He+ ion source.
A strongly focusing high-intensity He(+) ion source equipped with three concave electrodes has been designed and constructed as the beam source for a high-energy He(0) neutral beam probe system to diagnose fusion-produced alpha particles in thermonuclear fusion plasmas. The reduction of heat load onto the concave extraction electrodes is particularly important for a long pulse operation, as the heat load deforms the electrodes and thus the beam focal length. The effects on the arc efficiency (beam current/arc power) of the ion source due to the discharge filament structure (straight-type and L-shape-type filaments), size (filament diameters of 2 and 1.5 mm), number, and the locations have been studied. Choice of the appropriate filament structure improved the arc efficiency by 17%.
Kobuchi
T
T
School of Engineering, Tohoku University, Sendai 980-0579, Japan.
Kisaki
M
M
Shinto
K
K
Okamoto
A
A
Kitajima
S
S
Sasao
M
M
Tsumori
K
K
Kaneko
O
O
Sakakita
H
H
Kiyama
S
S
Hirano
Y
Y
Wada
M
M