Transmission and Absorption of Electromagnetic Waves in a Collisionless Plasma Slab

Abstract

An investigation is made of the propagation of electromagnetic waves normal to a plasma slab having a density gradient. The plane of polarization of waves is perpendicular to an external magnetic field. At resonances, a WKB-type approximation does not represent waves and an appreciable absorption appears due to infinitesimal collisions: the so called resonance absorption. The transmission and absorption coefficients are obtained in the limit of no collisions when in the slab the cut off is adjacent to the resonance.