Observation of fast ion behaviour with a neutron emission profile monitor in MAST

Abstract

Abstract Preliminary measurements of neutron emissivity at the Mega Amp Spherical Tokamak (MAST) along collimated lines-of-sight show a clear correlation between the neutron emissivity temporal and spatial evolution and the evolution of different MHD instabilities. In particular, the variations in neutron emissivity during sawtooth oscillations are compared with changes in the classical fast ion slowing-down time, while fast ion losses are observed in bursts during fishbones or as a continuous process during long-lived modes.