IAEA Fusion Energy Conference 2010

Proceedings of the 23rd IAEA Fusion Energy Conference
Daejeon, 11-16 October 2010

Organized by the International Atomic Energy Agency
and hosted by the Government of the Republic of Korea

IAEA-CN-180

(EXW/P2-12) Generation of Initial Closed Flux Surface by ECH at Conventional Aspect Ratio of R/a∼3; Experiments on the LATE device and JT-60U Tokamak

M. Uchida1), T. Maekawa1), H. Tanaka1), S. Ide2), Y. Takase3), F. Watanabe1), S. Nishi1)
 
1) Graduate School of Energy Science, Kyoto University, Kyoto 606-8502, Japan
2) Japan Atomic Energy Agency, Naka 311-0193, Japan
3) Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan

Abstract.  Generation of initial closed flux surface by electron cyclotron heating at a conventional aspect ratio of R/a∼3 has been investigated on LATE and further tested on the JT-60U Tokamak. In both experiments, the plasma current is initiated and increased by ECH under steady external fields composed of a toroidal field and a weak vertical field. In LATE experiments, a movable inboard limiter is used to change the aspect ratio of plasma up to R/a∼3. The results show that the formation of initial closed flux surface is still possible up to R/a∼3 while higher decay indices of vertical field are required as the aspect ratio increases. Similar current start-up discharges have been performed on JT-60U and the plasma current is initiated and increased up to 20 kA under the vertical field configuration having a high decay index.

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