Anomalous Fast-Ion Transport During Neutral Beam Injection on EAST

Resumo

The fast-ion transport during neutral beam injection on the Experimental Advanced Superconducting Tokamak (EAST) is studied. Based on the NUBEAM and TRANSP codes, it is found that fast-ion transport is anomalous when the minimum safety factor (q_min) is about 2, while it is neoclassical when q_min is around 1. Neutral beam injection heating efficiency, plasma stored energy, and the total heating power are reduced when the fast ion transport is anomalous. The Alfvén continuum spectrum and the mode structures of toroidal Alfvén eigenmodes (AEs) are also calculated for comparison between neoclassical fast-ion transport and anomalous fast-ion transport. High-q_min discharge with anomalous fast-ion transport has more AE activity than that of lower q_min discharge with neoclassical fast-ion transport.