Radially distributed instabilities and nonlinear process to generate pressure variation in a torus plasma

Naohiro Kasuya, Masatoshi Yagi

研究成果: ジャーナルへの寄稿学術誌査読

抄録

Distributed instabilities can successively change one after another to give accelerated radial propagation. The response of the linearly unstable distributed instabilities is identified in a gradual evolution phase as well as in a phase just after impact of modulation. Global nonlinear simulations of drift-interchange modes in helical plasmas are carried out with source modulation using a reduced MHD model. Conditional average of long time-series data with the modulation period reveals characteristic responses of the plasma. Smaller-scale variations comparable to the micro-temporal scale in this simulation are also included in the gradual evolution phase. The correlation analysis shows that the evolution of the mean pressure is strongly correlated with the strength of the nonlinear coupling. The evaluation of the energy balance to decompose the energy transfer into contribution from each three-wave coupling clarifies that a single mode coupling at each location has the dominant contribution to the smaller-scale pressure evolution in spite of self-organized mechanism with a wide range of comparable magnitude modes. Comparison of mode amplitudes does not define the dominant one, so identification of the active mode is useful for understanding the causality. This selection suggests the mechanism that gives the spreading effective in the quasi-steady state as for the ballistic propagation in the self-organized critical state.

本文言語英語
論文番号1303005
ジャーナルPlasma and Fusion Research
12
1
DOI
出版ステータス出版済み - 2017

!!!All Science Journal Classification (ASJC) codes

  • 凝縮系物理学

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