2024.01.10

[日時]　2024年1月17日（水） 13:30〜14:30

[場所]　核融合科学研究所 研究II期棟5階509セミナー室

[講師]　Gyungjin Choi 博士（ソウル大）

[講演題目]　Theory of direct fast ion effect on turbulence self-regulation

[講演概要]

 We present a mechanism for enhanced regulation of drift wave turbulence by zonal flows in the presence of a fast ion population. It demonstrates that dilution effects due to the energetic particles have a far-reaching impact on all aspects of the nonlinear dynamics. The modulational growth of zonal flow shear and the corresponding evolution of drift wave energy are calculated with dilution effects. The coupled zonal flow growth and drift wave energy equations are reduced to a predator–prey model. This is solved for the fixed points, which represent the various states of the system. Results display a strong dependence on dilution, which leads to greatly reduced levels of saturated turbulence and transport. Implications for the FIRE mode plasma of KSTAR are discussed in detail. This model is perhaps the simplest dynamical one that captures the beneficial effects of energetic particles on confinement.

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