Structure and overstability of resistive modes with runaway electrons

Chang Liu, Chen Zhao, Stephen C. Jardin, Amitava Bhattacharjee, Dylan P. Brennan, Nathanial M. Ferraro

Research output: Contribution to journalArticle

Abstract

We investigate the effects of runaway electron current on the dispersion relation of resistive magnetohydrodynamic modes in tokamaks. We present a new theoretical model to derive the dispersion relation, which is based on the asymptotic analysis of the resistive layer structure of the modes. It is found that in addition to the conventional resistive layer, a new runaway current layer can emerge whose properties depend on the ratio of the Alfvén velocity to the runaway electron convection speed. Due to the contribution from this layer, both the tearing mode and kink mode will have a real frequency in addition to a growth rate. The derived dispersion relation has been compared with numerical results using both a simplified eigenvalue calculation and a M3D-C1 linear simulation, and good agreement is found in both cases.

Original languageEnglish (US)
Article number092507
JournalPhysics of Plasmas
Volume27
Issue number9
DOIs
StatePublished - Sep 1 2020

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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    Liu, C., Zhao, C., Jardin, S. C., Bhattacharjee, A., Brennan, D. P., & Ferraro, N. M. (2020). Structure and overstability of resistive modes with runaway electrons. Physics of Plasmas, 27(9), [092507]. https://doi.org/10.1063/5.0018559