A Virtual Simons' Hour Talk: Suppression of Energetic Particle-Driven Instabilities in Stellarators

Given by: Donald Spong
   Plasma Theory and Modeling Group, Oak Ridge National Laboratory

Note the time: 8:00am EDT / 12:00 UTC.  Zoom link will be sent via email.

Abstract:  Good energetic particle (EP) confinement is essential for stellarators to achieve efficient heating and protection of plasma facing components. EP confinement is influenced by several mechanisms: classical orbit confinement, slowing-down timescales, and EP-driven instabilities. Stellarator optimization has recently made significant progress towards improved quasi-symmetry (which improves classical EP confinement). However, experimental evidence has shown that EP instabilities can enhance EP transport to levels of the same order as classical orbit losses. While EP instability driven transport can to some extent be influenced by profile control, three-dimensional shaping is also expected to affect these instabilities. Shaping can be used to control either the MHD wave structures that EP populations resonate with, or the particle-wave resonance dynamics. The physics of EP instabilities will be reviewed and some of the new possibilities for EP instability optimization targets described.