Nonlinear Decay and Plasma Heating by a Toroidal Alfv\'en Eigenmode

Nonlinear Decay and Plasma Heating by a Toroidal Alfvén Eigenmode

Z. Qiu, L. Chen, F. Zonca, and W. Chen

Phys. Rev. Lett. 120, 135001 – Published 27 March 2018

Abstract

We demonstrate theoretically that a toroidal Alfvén eigenmode (TAE) can parametrically decay into a geodesic acoustic mode and kinetic TAE in a toroidal plasma. The corresponding threshold condition for the TAE amplitude is estimated to be $| δ B_{⊥} / B_{0} | \sim O (10^{- 4})$ . Here, $δ B_{⊥}$ and $B_{0}$ are, respectively, the perturbed magnetic field of the pump TAE and the equilibrium magnetic field. This novel decay process, in addition to contributing to the nonlinear saturation of energetic-particle or $α$ -particle driven TAE instability, could also contribute to the heating as well as regulating the transports of thermal plasmas.

Received 23 November 2017

DOI:https://doi.org/10.1103/PhysRevLett.120.135001

Physics Subject Headings (PhySH)

Alfvén waves Magnetic confinement fusion Wave-wave, wave-particle interactions

Gyrofluid & gyrokinetics

Plasma Physics

Authors & Affiliations

Z. Qiu^1,*, L. Chen^1,2, F. Zonca^3,1, and W. Chen⁴

¹Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University, Hangzhou, People’s Republic of China
²Department of Physics and Astronomy, University of California, Irvine California 92697-4575, USA
³ENEA, Fusion and Nuclear Safety Department, C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Roma), Italy
⁴Southwestern Institute of Physics, P.O. Box 432 Chengdu 610041, People’s Republic of China