Theory of radiative shocks

Summary form only given. We have seen a sequence of recent experiments aimed at producing and studying radiative shocks. These experiments are opening the door to fundamental radiation hydrodynamic studies using laboratory tools. To complement such experiments, the author has done theoretical work, introducing new solution approaches that allow more complete treatment of some simple cases and providing a common treatment of radiative shocks in their various possible regimes. This presentation will emphasize the treatment of optically thick radiative shocks. This is a standard case in the literature, but the detailed sequence of developments is more complex than may seem likely at first glance. The approach and results of the theory will be summarized. In addition, the relation between such a simple theory and actual experiments will be discussed. An accurate theoretical treatment, even in an optically thick system, must account for the fact that the shock wave is inherently not in local thermodynamic equilibrium. The need of the shock to radiate strongly creates an optically thin cooling layer, whose thickness decreases as the shock becomes stronger. The penetration of radiative energy ahead of the shock is diffusive in the steady limit, yet this limit is very difficult to actually reach. A method for calculating profiles of the dynamical parameters quasi-analytically will be summarized. The key results can be obtained from more approximate energy-balance arguments, which will be presented