Analysis of fast-ion D_α data from the National Spherical Torus Experiment

摘要

Measured fast-ion D_α (FIDA) data from an extensive NSTX database are compared to 'classical' predictions that neglect transport by instabilities. Even in the absence of appreciable MHD, in many cases, the profile peaks at smaller major radius and the profile is broader than the predictions. Abrupt large-amplitude MHD events flatten the FIDA profile, as do most toroidal Alfven eigenmode (TAE) avalanche events. Generally, the onset of a long-lived mode also flattens the FIDA profile.