Journal of Statistical Physics, Vol. 97, Nos. 5/6, 1999. p. 941-955.
We present two approaches to the description of nonequilibrium radiation. The first approach is based on information statistical theory, whereas the second one is based on the hypothesis of radiative local thermodynamic equilibrium (RLTE). Both methods are applied to describe the radiation inside an infinite medium where a uniform temperature gradient has been established. The absorption coefficient is allowed to be frequency dependent. It is found that both approaches cannot be consistent beyond the first-order approximation. We argue that this shows the limitations of existing models of radiative transfer based on information theory.