Numerical Studies of Wave Trajectories and Electron Cyclotron Heating in Toroidal Plasmas

Abstract

Wave trajectories and cyclotron damping of the electromagnetic waves (O- and X-modes) and the electron Bernstein wave (B-mode) propagating in three dimensional toroidal plasmas are investigated, assuming the geometrical optics. Electron cyclotron heating (ECH) by injection of O- and X-mode is effective in low density (ω_pe<Ω_e≈ω), high electron temperature T_e plasmas in large tori. Here, ω_pe, Ω_e, and ω are the electron Langmuir, cyclotron and the applied frequencies, respectively. On the other hand, B-mode is effective for ECH on high density plasmas (ω_pe>Ω_e≈ω), where B-mode is linearly converted from X-mode or O-mode (the latter being converted to X- and then to B-mode). Because of strong damping, B-mode is also useful for low T_e plasmas. Propagation characteristics and mode-conversion in these high density plasmas are studied in detail.