X-ray Measurements during Plasma Current Start-up Experiments using the Lower Hybrid Wave on the TST-2 Spherical Tokamak

カテゴリ: 論文誌(論文単位)

グループ名: 【A】基礎・材料・共通部門

発行日: 2012/07/01

タイトル(英語): X-ray Measurements during Plasma Current Start-up Experiments using the Lower Hybrid Wave on the TST-2 Spherical Tokamak

著者名: Takuma Wakatsuki (The University of Tokyo), Akira Ejiri (The University of Tokyo), Hidetoshi Kakuda (The University of Tokyo), Yuichi Takase (The University of Tokyo), Takanori Ambo (The University of Tokyo), Hirokazu Furui (The University of Tokyo), Taka

著者名(英語): Takuma Wakatsuki (The University of Tokyo), Akira Ejiri (The University of Tokyo), Hidetoshi Kakuda (The University of Tokyo), Yuichi Takase (The University of Tokyo), Takanori Ambo (The University of Tokyo), Hirokazu Furui (The University of Tokyo), Takahiro Hashimoto (The University of Tokyo), Junichi Hiratsuka (The University of Tokyo), Hiroshi Kasahara (National Institute for Fusion Science), Kunihiko Kato (The University of Tokyo), Ryuhei Kumazawa (National Institute for Fusion Science), Yoshihiko Nagashima (Kyushu University), Kenji Saito (National Institute for Fusion Science), Takuya Sakamoto (The University of Tokyo), Tetsuo Seki (National Institute for Fusion Science), Fujio Shimpo (Kyushu University), Ryota Shino (The University of Tokyo), Takahiro Shinya (The University of Tokyo), Masateru Sonehara (The University of Tokyo), Osamu Watanabe (The University of Tokyo), Takashi Yamaguchi (The University of Tokyo), Charles P. Moeller (General Atomics)

キーワード: spherical tokamak，lower hybrid wave，X-ray measurements，plasma start-up，plasma current ramp-up

要約(英語): Non-inductive plasma current start-up experiments using RF power in the lower hybrid frequency range is being conducted on the TST-2 spherical tokamak. Plasma currents of up to 15 kA have been achieved. The effect of direct current drive can be seen by comparing the cases with co-drive and counter-drive. X-rays in various energy ranges were measured to investigate the interaction between the wave and the electrons. Soft X-ray (SX) measurements revealed that the perpendicular SX emission increased significantly as the plasma current increased, and that the tangential SX emission in the direction of RF drive was enhanced more strongly in the co-drive case compared to the counter-drive case. These observations imply that the fast electrons accelerated by the lower hybrid wave contribute to the plasma current. However, RF amplitude modulation experiments showed that the confinement time of these fast electrons are very short (less than 0.05 ms), much shorter than the collisional slowing down time. Hard X-ray spectral measurements showed that the radiation temperature of fast electrons in the co-direction for current drive was higher than that in the counter-direction. These observations are consistent with the existence of RF-driven fast electrons.

本誌: 電気学会論文誌A（基礎・材料・共通部門誌） Vol.132 No.7 （2012） 特集：The 16th International Workshop on Spherical Tori 2011

本誌掲載ページ: 485-489 p

原稿種別: 論文／英語

電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejfms/132/7/132_485/_article/-char/ja/