Electron landau damping of ion Bernstein waves in tokamak plasmas

摘要

Absorption of ion Bernstein(IB)waves by electrons is investigated. These waves are excited by linear mode conversion in tokamak plasma during fast wave(FW)heating and current drive experiments in the ion cyclotron range of frequencies. Near mode conversion, electromagnetic corrections to the local dispersion relation largely suppress electron Landau damping of these waves, which becomes important again, however, when their wavelength is comparable to the ion Larmor radius of shorter. The small Larmor radius wave equations solved by most numerical codes do not correctly describe the onset of electron Landau damping at very short wavelengths, and these codes, therefore, predict very little damping of IB waves, in contrast to what one would expect from the local dispersion relation.