Dynamics of low-$$n$$ shear Alfv$'e$n modes driven by energetic N-NB ions in JT-60U
Bierwage, A.; 藤堂 泰*; 相羽 信行; 篠原 孝司
Bierwage, A.; Todo, Yasushi*; Aiba, Nobuyuki; Shinohara, Koji
Dynamics of fast ions and shear Alfv$'e$n waves are simulated using MEGA, a global nonlinear hybrid code. The scenario is based on JT-60U shot E039672, driven by strong negative-ion-based neutral beams (N-NB), just before the onset of a so-called Abrupt Large Event (ALE). It is found that modes with toroidal mode numbers $$n$$ = 2, 3, 4 can be destabilized, besides the $$n$$ = 1 mode studied previously. The properties of the modes with n $$>$$ 1 are sensitive to the value of the plasma beta and the form of the fast ion distribution, so simulation conditions are set up as realistically as possible. When the fast ion drive exceeds a certain threshold, the $$n$$ = 3 mode is enhanced through a convective amplification process while following fast ions that were displaced by the field fluctuations. The fast ion transport in several cases is analyzed and implications of the results for the explanation of ALEs are discussed.
使用言語 : English
掲載資料名 : Nuclear Fusion
: 54
: 10
ページ数 : p.104001_1 - 104001_14
発行年月 : 2014/10
出版社名 : IOP Publishing
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キーワード : no keyword
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登録番号 : AA20130887
抄録集掲載番号 : 42001433
論文投稿番号 : 15059
Accesses  (From Jun. 2, 2014)
- Accesses
分野:Physics, Fluids & Plasmas
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