On the growth and decay of discontinuities in relativistic magnetogasdynamics

The modes of propagation of weak MHD shocks in relativistic fluids have been determined. The fundamental growth equation governing the growth and decay of a weak MHD wave has been obtained and solved under the assumption that the wave is propagating into a uniform medium at rest in the presence of a transverse magnetic field. The relativistic results are shown to be in full agreement with earlier results of classical magnetogasdynamics. The qualitative behaviour of the time-dependent wave amplitude of propagating weak MHD wave fronts has been studied. The problem of breakdown of weakwave solutions is studied and the consequent formation of shock waves has been discussed. A finite critical time is determined when a weak wave will terminate into a shock wave due to nonlinear steepening. It is also concluded that the relativistic effects somewhat delay the focusing phenomenon in spite of the quasilinear hyperbolic nature of the system of basic equations. (Auth.)