Interactions between MHD instabilities in the wall-stabilized high- plasmas

壁安定化された高プラズマにおけるMHD不安定性の相互作用

松永 剛; 相羽 信行; 篠原 孝司; 坂本 宜照; 武智 学; 鈴木 隆博; 朝倉 伸幸; 諫山 明彦; 大山 直幸; 吉田 麻衣子; 神谷 健作; 浦野 創; 仲野 友英; 鎌田 裕; JT-60チーム

Matsunaga, Go; Aiba, Nobuyuki; Shinohara, Koji; Sakamoto, Yoshiteru; Takechi, Manabu; Suzuki, Takahiro; Asakura, Nobuyuki; Isayama, Akihiko; Oyama, Naoyuki; Yoshida, Maiko; Kamiya, Kensaku; Urano, Hajime; Nakano, Tomohide; Kamada, Yutaka; JT-60 Team

In the JT-60U wall-stabilized high- plasmas, interactions between MHD instabilities have been observed. It is observed that an energetic particle driven wall mode (EWM) triggers an edge localized mode (ELM). When the EWM appears, type-I ELM crashes are synchronized with EWM bursts. The EWM-triggered ELMs have a higher frequency and less energy release than those of usual type-I ELMs. This interaction mainly occurs when the EWM with a large amplitude appears. In the SOL region, several measurements indicate ion losses induced by the EWM. Abrupt ion losses through the edge can increase as local pressure gradient at the pedestal that determines the edge stability. Moreover, another interaction that an EWM-triggered ELMs excites marginal resistive (RWM) is observed. Just after the EWM-triggered ELM, an distortion appears and decays soon. It is considered that an impact of the induced ELM can excite the marginally stable RWM.