Parametric Dependence Of Fast-ion Transport Events On The National Spherical Torus Experiment

[摘要] Neutral-beam heated tokamak plasmas commonly have more than one third of the plasma kinetic energy in the non-thermal energetic beam ion population. This population of fast ions heats the plasma, provides some of the current drive, and can affect the stability (positively or negatively) of magnetohydrodynamic instabilities. This population of energetic ions is not in thermodynamic equilibrium, thus there is free-energy available to drive instabilities, which may lead to redistribution of the fast ion population. Understanding under what conditions beam-driven instabilities arise, and the extent of the resulting perturbation to the fast ion population, is important for predicting and eventually demonstrating non-inductive current ramp-up and sustainment in NSTX-U, as well as the performance of future fusion plasma experiments such as ITER. This paper presents an empirical approach towards characterizing the stability boundaries for some common energetic-ion-driven instabilities seen on NSTX.

[发布日期] 2014-03-31

[学科分类] 原子、分子光学和等离子物理

[关键词] Alfven Waves;Fishbone Instability;Tokamaks;NSTX