Release Time:2019-03-11  Hits:

Indexed by: Journal Article

Date of Publication: 2018-02-01

Journal: PLASMA SCIENCE & TECHNOLOGY

Included Journals: CPCI-S、EI、SCIE

Volume: 20

Issue: 2

ISSN: 1009-0630

Key Words: post-cursor mode; H-mode; small ELM

Abstract: A 'post-cursor' quasi-coherent mode with frequency similar to 50 kHz has been observed following the crash of small edge localized modes (ELMs) in the Experimental Advanced Superconducting Tokamak by using a reciprocating Langmuir probe system inserted at the outboard midplane. This mode with strong potential and magnetic perturbations propagates in the electron-diamagnetic drift direction in the laboratory frame. In addition, these quasi-coherent fluctuations appear to be modulated by a MHD mode with lower frequency (similar to 5 kHz). The bi-coherence analysis shows that the post-cursor mode and the MHD mode have nonlinear interaction through three-wave coupling. The understanding on post-cursor mode can enhance our knowledge of ELMs and pedestal physics, and give new insight into the ELM process itself.