Compressional Alfvén eigenmodes excited by runaway electrons

Chang Liu, Dylan P. Brennan, Andrey Lvovskiy, Carlos Paz-Soldan, Eric D. Fredrickson, Amitava Bhattacharjee

Research output: Contribution to journalArticlepeer-review

Abstract

Compressional Alfvén eigenmodes (CAEs) driven by energetic ions have been observed in magnetic fusion experiments. In this paper, we show that the modes can also be driven by runaway electrons formed in post-disruption plasma, which may explain kinetic instabilities observed in DIII-D disruption experiments with massive gas injection. The spatial structure is calculated, as are the frequencies which are in agreement with experimental observations. Using a runaway electron distribution function obtained from a kinetic simulation, the mode growth rates are calculated and found to exceed the collisional damping rate when the runaway electron density exceeds a threshold value. The excitation of CAEs poses a new possible approach to mitigate seed runaway electrons during the current quench and surpassing the avalanche.

Original languageEnglish (US)
Article number036011
JournalNuclear Fusion
Volume61
Issue number3
DOIs
StatePublished - Mar 2021

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Keywords

  • Disruption
  • Kinetic instabilities
  • Runaway electrons

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