Suppressing magnetic island and accelerating its rotation by modulated resonant magnetic perturbation

摘要

A new method is investigated for stabilizing large magnetic islands or neoclassical tearing modes (NTMs) and for accelerating mode rotation by using modulated resonant magnetic perturbation (RMP). The RMP is applied via feedback control only when the phase difference between the mode and RMP is in the range of π ≤ Φ ≤ 2π. Nonlinear numerical modeling based on reduced magnetohydrodynamics (MHD) equations has been carried out. It is found that the mode/island can be either completely or substantially suppressed, when the RMP is applied in the phase region π ≤ Φ ≤ 1.5π or π ≤ Φ ≤ 2π. The mode frequency is significantly increased for the second case. This method can also be utilized for avoiding mode locking, which often triggers plasma disruption.