Hydrodynamical description of a photon gas in magnetized plasmas

The propagation for relativistically intense and broad spectrum EM waves in magnetized plasmas is considered. A general kinetic equation for the photon spectral function is derived and used to obtain a set of hydrodynamical equations for the particular case of helicon waves. Numerical calculations for the 1-D set of equations with a Gaussian distribution function at t = 0 shows that the profile of density changes its shape in the course of time and forms a discontinuity. (orig.)