Trapping of an electromagnetic wave by a nonstationary plasma layer

Summary form only given. We show that electromagnetic energy can be effectively trapped by a plasma layer whose electron density is growing rapidly. The trapping is realized via partial transformation of the electromagnetic wave incident on the layer into the surface waves which are guided by the layer. For the gaseous plasma layer two surface waves propagating in the opposite directions are excited; those waves are equally frequency downshifted compared with the frequency of the incident wave.