Conditions for the generation of supersonic diffusive radiation transport

Radiation transport in matter can be supersonic when the Mach number of the heat wave front is typically over 3. In this paper, the conditions under which the supersonic radiation transport was diffusive were investigated in the case of an external radiation source with constant temperature. This model was based on the analytic theory of the radiation diffusion equation in one dimension. The ranges of parameters where supersonic diffusive transport occurs were obtained for a fixed mass density in an analytical way. Furthermore, critical values for the temperature of the external radiation source and the radiation heat wave front position were also derived analytically. They are the functions of the mass density. A calculating case for SiO2 foam is presented to show the basic physical pictu