Recent progress on TRIAM-1M

H. Zushi, S. Itoh, K. N. Sato, K. Nakamura, M. Sakamoto, K. Hanada, E. Jotaki, K. Makino, Y. D. Pan, S. Kawasaki, H. Nakashima

研究成果: Contribution to journalArticle査読

10 被引用数 (Scopus)

抄録

A steady state plasma with high performance and high current drive efficiency is reported. In 2.45 GHz LHCD plasmas Ti is studied as a function of ne at the edge of the high ion temperature (HIT) window. Different characteristic timescales are found for Ti and ne to enter the HIT regime and the observed hysteresis behaviour of Ti with respect to ne is attributed to this difference. The electromagnetic emission (<3.5 GHz) is studied in order to understand ion heating mechanisms in the HIT regime. The spectrum shows several sidebands whose peak frequencies correspond to the ion plasma frequency. The spectral narrowing of the width of the sideband shows a clear correlation with ion heating. In 8.2 GHz LHCD plasmas an enhanced current drive (ECD) regime where both current drive efficiency ηCD (= n̄eICDR0/PLH approx. 1 × 1019 A m-2 /W) and energy confinement time τE (approx. 8-10 ms) are simultaneously improved is obtained at an n̄e of 4.3 × 1013 cm-3 and B = 7 T under full current drive conditions. There exists a certain threshold power above which the ECD transition occurs. A hysteresis of ηCD is found around the threshold power, which is explained by the different characteristic time for the ECD transition in power rampup and rampdown schemes. Current profile control experiments are performed by using two opposite travelling LHWs. Current compensation (ΔICD/ICD < -10%) is clearly seen when the backward (BW) travelling LHW (8.2 GHz) is added to a target plasma whose current is driven by a forward travelling LHW (8.2 GHz). As the BW wave power is increased, however, the current tends to flow in the forward direction. The mechanisms of this non-linear behaviour of the driven current with respect to the BW wave power are discussed.

本文言語英語
ページ(範囲)1183-1196
ページ数14
ジャーナルNuclear Fusion
40
6
DOI
出版ステータス出版済み - 6 1 2000

All Science Journal Classification (ASJC) codes

  • 核物理学および高エネルギー物理学
  • 凝縮系物理学

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