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

Abstract

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 3 D 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.

Keywords

• impurity radiation
• tearing mode
• magnetic island braking
• higher-n mode
• island formation