INFORMATION-THEORETICAL APPROACH TO RADIATIVE-TRANSFER

The maximum entropy formalism is used to obtain the radiation and matt er distribution functions for radiative systems in steady nonequilibri um states, under the gray approximation. The radiation distribution fu nction is expanded in a smallness parameter, which vanishes at equilib rium. In the first near-equilibrium approximation, we derive the resul ts of near-equilibrium diffusion theory. This may be regarded as an an alogue to the kinetic-theoretical result, according to which in the fi rst Enskog approximation, the Fourier heat conduction equation is obta ined. The theory is also developed up to the second order, leading to results which apply to situations further away from equilibrium than t hose corresponding to near-equilibrium diffusion theory. A simple appl ication is analyzed.