Alfven eigenmodes including magnetic island effects in the TJ-Ⅱ stellarator

摘要

Coherent modes in NBI-heated plasmas of the TJ-Ⅱ stellarator at frequencies generally below those of helicity induced Alfven eigenmodes (f＜f_(HAE)) are explained as global Alfven eigenmodes (GAE) and discrete shear-Alfven eigenmodes induced by a non-rotating magnetic island (MIAE). Rotating islands are also found to interact with Alfven eigenmodes: if they share the same helicity, they disturb each other; otherwise, new Alfven modes can be excited via wave-wave coupling.