Non-inductive start up of QUEST plasma by RF power

K. HANADA; H. ZUSHI; H. IDEI; K. NAKAMURA; M. ISHIGURO; S. TASHIMA; E. I. KALINNIKOVA; M. SAKAMOTO; M. HASEGAWA; A. FUJISAWA; A. HIGASHIJIMA; S. KAWASAKI; H. NAKASHIMA; H. LIU; O. MITARAI; T. MAEKAWA

Plasma Science and Technology > 2011 > 13(3): 307-311.

K. HANADA, H. ZUSHI, H. IDEI, K. NAKAMURA, M. ISHIGURO, S. TASHIMA, E. I. KALINNIKOVA, M. SAKAMOTO, M. HASEGAWA, A. FUJISAWA, A. HIGASHIJIMA, S. KAWASAKI, H. NAKASHIMA, H. LIU, O. MITARAI, T. MAEKAWA. Non-inductive start up of QUEST plasma by RF power[J]. Plasma Science and Technology, 2011, 13(3): 307-311.

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Non-inductive start up of QUEST plasma by RF power

a): Research Institute for Applied Mechanics, Kyushu University, Japan, b):Interdisciplinary Graduate School of Engineering Science, Kyushu University, Japan, c): School of Industrial Engineering, Tokai University, Japan d):Graduate School of Energy Science, Kyoto University, Japan, e): Graduate School of Technology, Kyoto University, Japan f): Graduate School of Frontier Science, University of Tokyo, Japan g): Institute of Plasma Physics, Chinese Academy of Sciences, China.

Funds: This work is performed with the support and under the auspices of the NIFS Collaboration Research Program (NIFS05KUTR014, NIFS08KUTR022). This work is partially supported by a Grant-in-aid for Scientific Research from Ministry of Education, Culture, Sports, Science and Technology of Japan. This work was also partially supported by the JSPS-CAS Core-University program in the field of ‘Plasma and Nuclear Fusion' and the Collaborative Research Program of Research Institute for Applied Mechanics, Kyushu University.

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Corresponding author:
K. HANADA, E-mail: hanada@triam.kyushu-u.ac.jp

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Abstract

Abstract

Both start-up and sustainment of plasma were successfully achieved by fully non-inductive current drive using microwave with a frequency of 8.2 GHz. Plasmas current of 15 kA was implemented for 1 s. Magnetic surface reconstruction exhibited a plasma shape with an aspect ratio of below 1.5. The plasma current was dependent significantly on the launchen microwave power and vertical magnetic field, whiile not affected by the mode of launched wave and the toroidal refractive index. Hard X-ray (HXR) emitted from energetic electrons accelerated by the microwave was observed, and the discharge with a plasma current over 4 kA followed the same trend as the number of photons of 10 to 12 keV. This suggests that the plasma current may be driven by energetic electrons. Based on the experimental conditions, alternative explanations of how the plasma current could be driven are discussed.
- Steady state operation of spherical tokamak,
- non-inductive current drive,
- QUEST