On the Toroidal Plasma Rotations Induced by Lower Hybrid Waves

Guan, Xiaoyin ; Qin, Hong ; Liu, Jian ; Fisch, Nathaniel J.

关键词: Lower Hybrid Waves;    Transport Theory;   

DOI  :  10.2172/1056357
RP-ID  :  PPPL-4831
PID  :  OSTI ID: 1056357

美国|英语

来源: SciTech Connect

【 摘 要 】

A theoretical model is developed to explain the plasma rotations induced by lower hybrid waves in Alcator C-Mod. In this model, torodial rotations are driven by the Lorentz force on the bulk electron flow across flux surfaces, which is a response of the plasma to the resonant-electron flow across flux surfaces induced by the lower hybrid waves. The flow across flux surfaces of the resonant electrons and the bulk electrons are coupled through the radial electric fi eld initiated by the resonant electrons, and the friction between ions and electrons transfers the toroidal momentum to ions from electrons. An improved quasilinear theory with gyrophase dependent distribution function is developed to calculate the perpendicular resonant-electron flow. Toroidal rotations are determined using a set of fluid equations for bulk electrons and ions, which are solved numerically by a fi nite- difference method. Numerical results agree well with the experimental observations in terms of flow pro file and amplitude. The model explains the strong correlation between torodial flow and internal inductance observed experimentally, and predicts both counter-current and co-current flows, depending on the perpendicular wave vectors of the lower hybrid waves. __________________________________________________