The effect of radiation energy loss on shock wave propagation

Abstract

The propagation of shock wave induced by supernovae is reconsidered, taking into account the energy loss due to thermal radiation. At the early stage of the shock, the energy loss can be considered as a perturbation. We derived the first order equations for the distributions of velocity, density and pressure in the shock. A numerical solution shows that, due to this perturbation, the central pressure will be greatly reduced with time. When the central pressure becomes negligible, the propagation of the shock is effectively driven-free. So we re-defined the starting time, τ A , of the effectively driven-free stage as the time when the central pressure is reduced to one half of its initial value. Then we found that up to the time τ A , the energy loss only amounts to about 10% of its initial value. Thus, it is an overestimate to define the starting time of the effectively driven-free stage as the time when one half of the initial energy has been lost.