Mode conversion of lower-hybrid waves

Abstract

In an inhomogeneous plasma, partial conversion of lower-hybrid waves to ion plasma waves can occur for a range of plasma parameters, even in the absence of a reflection layer. Nonetheless, mode conversion may be significantly reduced if the plasma is sufficiently dissipative. If electron Landau damping is a dominant dissipation mechanism, the quasi-linear behavior of the electron distribution function can introduce a strong rf power dependence into the mode conversion efficiency. At low rf power levels the damping may be too large to permit effective mode conversion, while above some critical power level, the quasi-linear flattening of the distribution function may sufficiently reduce the damping to permit strong mode conversion.