Stimulated electromagnetic shock radiation (SESR) in frequency-dispersive media

Abstract

The interaction in a frequency-dispersive medium of a coherent electromagnetic wave with an electron moving faster than a critical (Mach) speed produces electromagnetic radiation with novel characteristics. Theory predicts emission of intense radiation in the form of shock fronts at specific angles from the electron trajectory. The shock fronts are correlated with specific frequencies shifted significantly from that of the incident wave. We have named this effect stimulated electromagnetic shock radiation (SESR). The shock frequencies depend dynamically on the populations of the energy levels that give rise to the medium resonances. A given shock frequency changes from below to above the resonance frequency of the medium with which it is associated as the populations of the two energy levels corresponding to this resonance frequency change from an equilibrium distribution to an inverted one. This dynamic resonance crossing points to the possibility of new synergisms between SESR emission and stimulated emission between discrete levels.