Increasing the beam power of the JT-60U negative ion based neutral beam system

Author

Kuriyama, M. ; Akino, N. ; Ebisawa, N. ; Grisham, L. ; Hikita, S. ; Honda, A. ; Itoh, T. ; Kawai, M. ; Kazawa, M. ; Kusaka, M. ; Mogaki, K. ; Nagase, N. ; Ohga, T. ; Okumura, Y. ; Oohara, H. ; Satoh, F. ; Seki, H. ; Tanai, Y. ; Toyokawa, Y. ; Umeda, N. ;

Author_Institution

Naka Fusion Res. Establ., JAERI, Ibaraki, Japan

fYear

1999

fDate

1999

Firstpage

133

Lastpage

136

Abstract

In the negative ion based NBI for JT-60, the maximum injection power reached so far is 5.2 MW at 350 keV. However the beam power and pulse duration are limited mainly by a mismatched perveance of the accelerated beam due to the source plasma non-uniformity. The source plasma uniformity was investigated by measuring the arc current distribution and ion saturation current in the plasma generator. A large non-uniformity has been found at the bottom side along a longitudinal direction in the ion source. As countermeasures against the source plasma non-uniformity, the adjustment of resistors in series with are current circuit connected to each of eight filament groups and the masking both fringes of the plasma grid are effective

Keywords

Tokamak devices; fusion reactor design; plasma beam injection heating; 350 keV; 5.2 MW; JT-60U; arc current distribution; beam power; ion saturation current; negative ion based NBI; negative ion based neutral beam injection; Acceleration; Circuits; Current distribution; Current measurement; Ion sources; Particle beams; Plasma accelerators; Plasma measurements; Plasma sources; Resistors;

fLanguage

English

Publisher

ieee

Conference_Titel

Fusion Engineering, 1999. 18th Symposium on

Conference_Location

Albuquerque, NM

Print_ISBN

0-7803-5829-5

Type

conf

DOI

10.1109/FUSION.1999.849806

Filename

849806