Effects of hydrodynamical echo in a plasma-like media bounded by a metal

Summary form only given. The possibility of the existence of hydrodynamic echo effects in both gas and semiconductor plasmas bounded by a metal wall has been demonstrated. This effect has been made possible by the fact that small-scale oscillations in the vicinity of local resonances may make it possible to retain the phase memory about the initial perturbations. It is shown that this effect may be used in diagnostics of near-surface transient layers in semiconductor and gas plasmas. Specifically, the authors have considered the process of temporal two-pulse hydrodynamic echo of surface plasmon-polariton modes propagating across the external magnetic field at the interface between a semiconductor plasma with a nonuniform near-surface region and a metal. The criterion of the echo effect´s existence and expressions for the signal electromagnetic fields have been obtained. The time of generation of the plasma response is dependent on the parameters of the transient layer and provides information about the density profile.