Wave Trajectories and Damping of Lower Hybrid Wave in Tokamak Plasmas

Incident lower hybrid waves (LHW) propagate toward the center of the plasma in a spiral form in the poloidal and the toroidal sections, and finally are absorbed by the ion Landau damping (ILD) and/or the electron Landau damping (ELD) in accordance with the refractive index parallel to the magnetic field N‖, which is varied considerably along the trajectory because of the toroidicity and the rotational transform. We propose the scaling law of the wave trajectories on plasma parameters, which shows that the control of N‖ or the applied frequency is necessary during the lower hybrid heating (LHH).