Magnetic island formation and rotation braking induced by low-Z impurity penetration in an EAST plasma

Recent observations of the successive formations of the 4/1, 3/1, and 2/1 magnetic islands as well as the subsequent braking of the 2/1 mode during a low-Z impurity penetration process in EAST experiments are well reproduced in our 3D resistive MHD simulations. The enhanced parallel current perturbation induced by impurity radiation predominately contributes to the tearing mode growth, and the 2/1 island rotation is mainly damped by the impurity accumulation as results of the influence from high n modes.

Automated summary

The successive formations of the 4/1, 3/1, and 2/1 magnetic islands as well as the subsequent braking of the 2/1 mode during a low-Z impurity penetration process in EAST experiments are accurately reproduced in our 3D resistive MHD simulations. The tearing mode growth is mainly driven by the enhanced parallel current perturbation induced by impurity radiation, while the damping of the 2/1 island rotation is primarily caused by the impurity accumulation influenced by high n modes.