Full suppression of Edge Localised Modes with non-axisymmetric magnetic perturbations at low plasma edge collisionality in ASDEX Upgrade

摘要

Full suppression of Edge Localised Modes (ELMs) by small non-axisymmetric magnetic perturbations (MP) of high-confinement-mode (H-mode) plasmas is one of the most promising techniques for ITER to avoid excessive erosion of the first wall due to the impulsive energy losses induced by ELMs. However, few experiments have so far reproduced the DIII-D ELM suppression scenario [1] and full ELM suppression has long been searched for in ASDEX Upgrade (AUG) [2]. Previous experiments in AUG were performed at low triangularity, however, a recent AUG/DIII-D similarity experiment [3] has shown that it is important to increase the triangularity in order to achieve full ELM suppression in AUG [4], The observation of an increased edge pressure gradient at elevated triangularity [3] suggests stronger amplification of the externally applied MP by marginally stable kink-peeling modes [5] as a possible origin of the plasma shape dependence.