Impact of rotational-transform profile control on plasma confinement and stability in CHS

摘要

In neutral beam heated plasmas of CHS, which is a low aspect-ration heliotron/torsatron device, the effect of rotational transform ((iota)) profile shape on plasma confinement and stability is studied by inducing a net plasma current (Ip). In the case that the external (iota) is increased by Ip, very rapid H-mode transition (within (approx)0.2 ms) is observed at the thresholds of Ip and heating power, having all characteristics found in the tokamak H-mode. There is no obvious difference in the H-mode characteristics between deuterium and hydrogen plasmas. In the opposite case that the external (iota) is decreased by reversing Ip, the H-mode transition is not observed. (author). (ERA citation 20:011815)