Properties of thermal decay and radiative collapse of NBI heated plasmas on lhd

摘要

In LHD discharges, the NBI heated plasmas are terminated in two ways: (a) thermal decay (TD) after the termination of NBI and (b) radiative collapse (RC0 during the NBI heating. The basic characteristics of the TD and RC discharges are compared. It is found that the decay and collapse of the plasma are mainly governed by the heating power and the plasma density. The critical density n_c for the collapse of RC plasmas is similar to the scaling laws obtained in other helical devices, i.e. n_c ∝ (PB/V)~0.5. where P. B and V denote heating power, magnetic field and plasma volume, respectively.