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 |δB/B0|∼O(10-4). Here, δB and B0 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.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
Qiu, Z., Chen, L., Zonca, F., & Chen, W. (2018). Nonlinear Decay and Plasma Heating by a Toroidal Alfvén Eigenmode. Physical Review Letters, 120(13), -. . https://doi.org/10.1103/PhysRevLett.120.135001