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arXiv · 2103.09446

Nonlinear coupling of reversed shear Alfven eigenmode and toroidal Alfven eigenmode during current ramp

Shizhao Wei·Yahui Wang·Peiwan Shi·Wei Chen·Ningfei Chen·Zhiyong Qiu
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Abstract

Two novel nonlinear mode coupling processes for reversed shear Alfven eigenmode (RSAE) nonlinear saturation are proposed and investigated. In the first process, RSAE nonlinearly couples to a co-propagating toroidal Alfven eigenmode (TAE) with the same toroidal and poloidal mode numbers, and generates a geodesic acoustic mode (GAM). In the second process, RSAE couples to a counter-propagating TAE and generates an ion acoustic wave quasi-mode (IAW). The condition for the two processes to occur is favored during current ramp. Both processes contribute to effectively saturate the Alfvenic instabilities, as well as nonlinearly transfer of energy from energetic fusion alpha particles to fuel ions in burning plasmas.

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Shizhao Wei, Yahui Wang, Peiwan Shi, Wei Chen, Ningfei Chen, Zhiyong Qiu. 2021-03-17. Nonlinear coupling of reversed shear Alfven eigenmode and toroidal Alfven eigenmode during current ramp. https://doi.org/10.1088/0256-307x%2F38%2F3%2F035201

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