Observation of hysteretic magnetic island response to resonant magnetic perturbation in LHD

The hysteretic magnetic island response to an externally applied resonant magnetic perturbation (RMP) field is observed in the LHD. Thresholds of the amplitude of the RMP for the growth/healing transition of the magnetic island differ. In the case that the RMP is ramped up, that field is initially shielded and the magnetic island is healed. After that, when the increasing RMP exceeds a threshold, that field penetrates into the plasma and the magnetic island appears. In the case that the RMP is ramped down, the threshold of the RMP for island healing is smaller than that for growth. (author)