A brief review: effects of resonant magnetic perturbation on classical and neoclassical tearing modes in tokamaks

This paper reviews the effects of resonant magnetic perturbation (RMP) on classical tearing modes (TMs) and neoclassical tearing modes (NTMs) from the theory, experimental discovery and numerical results with a focus on four major aspects: (ⅰ) mode mitigation, where the TM/NTM is totally suppressed or partly mitigated by the use of RMP; (ⅱ) mode penetration, which means a linearly stable TM/NTM triggered by the externally applied RMP; (ⅲ) mode locking, namely an existing rotating magnetic island braked and finally stopped by the RMP; (ⅳ) mode unlocking, as the name suggests, it is the reverse of the mode locking process. The key mechanism and physical picture of above phenomena are revealed and summarized.