摘要
A ‘post-cursor＇ quasi-coherent mode with frequency -50 k Hz 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 electrondiamagnetic drift direction in the laboratory frame.In addition,these quasi-coherent fluctuations appear to be modulated by a MHD mode with lower frequency（-5 k Hz）.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.
A ‘post-cursor＇ quasi-coherent mode with frequency -50 k Hz 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 electrondiamagnetic drift direction in the laboratory frame.In addition,these quasi-coherent fluctuations appear to be modulated by a MHD mode with lower frequency（-5 k Hz）.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.
基金
supported by the National Magnetic Confinement Fusion Science Program of China under Grant Nos.2015GB101000,2014GB124000
National Natural Science Foundation of China under Grant Nos.11322549,11422546,11505222,11505220
the Sino Danish Center for Education and Research
