Density-modulation effects on the propagation of an electromagnetic wave in a plasma

The propagation of an electromagnetic wave through a transparent plasma characterized by a spatial modulation of the density in the direction of propagation is analysed by computing the reflection coefficient of a single plasma slab and then that relevant to a set of many identical or slightly different slabs. The transmission spectra relevant to different density profiles of a single slab are computed to show the effects of (a) the density gradient, (b) a slight non-uniformity among adjacent slabs and (c) plasma modulation on the linear cut-off.