2014/01/27 by O. Jones, O M Jones, C. Michael +36
Physics and Astronomy · #FOS: Physical sciences #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Plasma Physics (physics.plasm-ph) #Solar and Space Plasma Dynamics #physics.plasm-ph
paper · pdf · doi:10.48550/arxiv.1401.6864
28 pages, 18 figures
arxiv created 2014/01/27 · openalex publication_date 2014/01/27 · arxiv updated 2014/01/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The results of a comprehensive investigation into the effects of various MHD modes on the NBI-generated fast-ion population in MAST plasmas are reported. Fast-ion redistribution due to low-frequency (20-50 kHz) chirping energetic particle modes known as fishbones, as well as the long-lived internal kink mode, is observed with the Fast-Ion Deuterium Alpha (FIDA) spectrometer and radially-scanning collimated neutron camera. In addition, strongly-driven chirping toroidicity-induced Alfven eigenmodes are observed to cause fast-ion redistribution, as are sawteeth and large edge-localised modes. In each case, the modes affect fast ions in a region of real space governed by the eigenmode structure and principal toroidal mode number. Modelling using the global transport analysis code TRANSP, with ad hoc anomalous diffusion introduced, reproduces the coarsest features of the affected fast-ion distribution in the presence of energetic-particle-driven modes, but the spectrally and spatially resolved FIDA measurements suggest that the distribution exhibits structure on a finer scale than is accounted for by this model.