A self-consistent shock solution for radiation-dominated flows

Abstract

The structure of a one-dimensional plane-parallel shock in a radiation-dominated hot plasma flow is investigated numerically. Compton scattering with the electrons is assumed to be the dominant energy exchange mechanism between the plasma and the radiation. A self-consistent solution is obtained for the photon spectrum, the velocity, and the temperature profile in the shock. Two types of shock structures are found, depending on the initial conditions: those where deviations from a local equilibrium spectrum are small with a temperature function increasing monotonically through the shock, and those where close to the shock center the spectrum shows a strongly nonequilibrium behavior and the temperature assumes a maximum before it decreases to its final adiabatic value. This general shock structure depends on the ratio of two length scales, namely the typical shock width and a thermalization length which describes the relaxation toward the postshock equilbrium; an analytic estimate of this length scale is given.