Two species drag/diffusion model for energetic particle driven modes
Abstract
A nonlinear bump-on-tail model for the growth and saturation of energetic particle driven plasma waves has been extended to include two populations of fast particles—one dominated by dynamical friction at the resonance and the other by velocity space diffusion. The resulting temporal evolution of the wave amplitude and frequency depends on the relative weight of the two populations. The two species model is applied to burning plasma with drag-dominated alpha particles and diffusion-dominated ICRH accelerated minority ions, showing the stabilization of bursting modes. The model also suggests an explanation for the recent observations on the TJ-II stellarator, where Alfvén Eigenmodes transition between steady state and bursting as the magnetic configuration varied.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 01, 2017
- Source ID
- 10.1063/1.4996123
Entities
People
- D. A. Spong
- M. Porkolab
- S. E. Sharapov
- V Aslanyan
Organizations
- Culham Centre for Fusion Energy
- Massachusetts Institute of Technology
- Oak Ridge National Laboratory
- Research Councils UK
- United States Department of Energy