The Quasi-stationary Structure of Radiating Shock Waves II. The Two-temperature Fluid

Abstract

We solve the equations of radiation hydrodynamics in the two-temperature fluid approximation on an adaptive grid. The temperature structure depends upon the electron-ion energy exchange length, $l_{ei}$, and the electron conduction length, $l_{ec}$. Three types of radiating shock structure are observed: subcritical, where preheating of the unshocked gas is negligible; electron supercritical, where radiation preheating raises the temperature of the unshocked electron fluid to be equal to the final electron temperature; supercritical, where preheating and electron-ion energy exchange raise the preshock $T_{e,i}$ to their final post shock values. No supercritical shock develops when $l_{ei}$ is larger than the photospheric depth of the shocked gas because a negligible amount of the ion energy is transferred to the electrons and the shock is weakly radiating. Electron conduction smooths the $T_e$ profile on a length scale $l_{ec}$, reducing the radiation flux.