A branch of energetic-particle driven geodesic acoustic modes due to magnetic drift resonance

M. Sasaki, N. Kasuya, K. Itoh, K. Hallatschek, M. Lesur, Y. Kosuga, S. I. Itoh

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14 Citations (Scopus)

Abstract

Eigenmode analysis of geodesic acoustic modes (GAMs) driven by fast ions is performed, based on a set of gyrokinetic equations. Resonance to the magnetic drift of the fast ions can destabilize GAMs. A new branch is found in the family of GAMs, whose frequency is close to the magnetic drift frequency of the fast ions. The poloidal eigenfunction of this branch has bump structures in the poloidal direction where the resonance of the magnetic drift with the mode is strong. The ion heating rate by the GAMs is evaluated in the framework of quasi-linear theory. The heating is localized poloidally around the resonance locations. Owing to the bumps in the eigenfunction, the magnitude of the heating is much larger than that estimated without the magnetic drift resonance.

Original languageEnglish
Article number102501
JournalPhysics of Plasmas
Volume23
Issue number10
DOIs
Publication statusPublished - Oct 1 2016

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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