Cherenkov radiation of a fast electron in ultrashort intense laser plasmas

The Cherenkov radiation resulting from a fast electron in ultrashort intense laser plasma is explored theoretically based on the density perturbation theory. The radiation emitting conditions and characteristics of the corresponding Cherenkov geometry are discussed in detail. By numerical computation, a significant conclusion is revealed that the THz radiation of Cherenkov-type can be excited by the coupling of a fast electron produced by an intense ultrashort pulse laser and plasma medium in specifically parameter conditions. The results show that the radiation intensity is strongly dependent on the pulse duration of incident laser and the velocity of a fast electron, the emission spectrum width is dependent on the plasma density and the ratio of a fast electron and laser group velocities, and the emission angle distribution is dependent on the effective radius of laser beam. (c) 2007 American Institute of Physics.