RADIATIVE-TRANSFER WITHIN THE FRAMEWORK OF EXTENDED IRREVERSIBLE THERMODYNAMICS

In Extended Irreversible Thermodynamics (EIT) in addition to a set of extensive quantities the dissipative part of the conductive fluxes of these quantities is used to describe the non-equilibrium state of a continuum. We show that an appropriate integration of the radiative transfer equation yields relations similar to those assumed in EIT. It is possible to establish a Gibbs fundamental equation which allows treatment of the problem of radiative transfer within the framework of irreversible thermodynamics. The formalism of EIT is used to state closure assumptions for the local production of radiation energy, the flux of radiation energy, and the radiation stress tensor. Here a large number of phenomenological coefficients arise. If these are known one can avoid an explicit integration of the radiative transfer equation, thereby simplifying enormously the mathematical problems in radiation hydrodynamics.