Interaction of intense laser pulse with a thin flying plasma mirror and generation of high frequency radiations

An electromagnetic wave reflected from a moving mirror undergoes frequency multiplication and corresponding increase in the electric field amplitude. This multiplication factor is proportional to the square of the relativistic gamma factor of the mirror. This effect is an attractive basis for the source of a powerful high frequency radiation. In relativistic plasma, the double Doppler effect manifests itself when a fast change in the electric current density leads to the conversion of an incident light into strong compressed pulses of high frequency electromagnetic radiation. Here we discuss intense laser driven high frequency radiation of high intensity as a result of reflection of electromagnetic wave from a relativistic flying plasma mirror. As regards the brightness of reflected radiation we are concerned with the light energy emerging from a portion of the mirror surface. If the mirror surface is opaque, it is reflected light which is considered; if it is transparent or semi-transparent (in which case the light is partly absorbed or scattered), it is the transmitted light which is usually measured. We present our analytical and numerical results on the number of emitted energetic x-ray photons and their possible medical applications. (author)