Spontaneous emission of waves by a fast shock wave in a longitudinal magnetic field

The stability of a fast longitudinal shock wave against weak perturbations of the discontinuity surface is investigated within the framework of ideal magnetohydrodynamics. It is shown that the region of spontaneous emission of waves by the discontinuity in a plasma with an arbitrary equation of state is determined by the magnetic field, and is broader than the corresponding region in ordinary hydrodynamics. In a sufficiently strong magnetic field, the spontaneous wave emission by the discontinuity can occur in an ideal gas with a constant specific heat