Power deposition of ion Bernstein wave heating on the HT-7 tokamak

Efficient direct heating of electrons by ion Bernstein waves has been obtai ned on the HT-7 tokamak. Off-axis heating, which is considered to be the re sult of electron Landau damping, was observed and studied by means of soft x-ray imaging. The measured power deposition was found to be independent of magnetic field through scanning the toroidal field from 1.5 to 1.7T, in co ntrast to the ion heating results. It is suggested that the electron Landau damping is dominant in this heating regime.