(EX/P6-14) Control of Non-inductive Current in Heliotron J

K. Nagasaki1), K. Nagasaki1), G. Motojima2), M. Nosaku2), H. Okada1), T. Mizuuchi1), S. Kobayashi1), K. Sakamoto1), K. Kondo2), Y. Nakamura2), H. Arimoto2), S. Watanabe2), S. Matsuoka2), T. Tomokiyo2), K. Y. Watanabe3), A. Cappa4), F. Sano1)
 
1) Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan
2) Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan
3) National Institute for Fusion Science, Toki, Gifu, Japan
4) Laboratorio Nacional de Fusión, EURATOM-CIEMAT, Madrid, Spain

Abstract.  Non-inductive current including bootstrap current and EC driven current has been studied in Heliotron J ECH plasmas. The Heliotron J device has a high flexibility to control the magnetic field spectrum, making it possible to investigate the field configuration effect on the non-inductive current. The non-inductive current is accurately measured in the absence of Ohmic current without affecting plasma confinement. The measured toroidal current at medium density ( ne = 1.0×1019 m-3) agrees with a theoretical prediction of bootstrap current considering the configuration effect. The ECCD determined by the balance between the Fisch-Boozer and Ohkawa effects is controlled by the EC power deposition and magnetic field configuration. Net free current state has been experimentally demonstrated by compensating the bootstrap current with the EC current.

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