Plasma Wave Reflection in Slowly Varying Media

Abstract
Two mathematical formalisms are presented to describe wave reflection in a slowly varying spatially inhomogeneous thermal plasma described by the Vlasov equation. It is found that the transmitted wave, which is the Wentzel-Kramer-Brillouin solution, and the reflected wave, can be expressed in terms of the local dielectric properties of the medium. In a numerical example, it is shown that the intrinsic thermal properties of the plasma can supply reflection mechanisms that compete with the reflection coefficient predicted when the plasma is described by fluid equations.