Thermodynamics of nonequilibrium radiation. (I) General theory

An in-depth study of the thermodynamics of nonequilibrium radiation is pres ented, The characterization of its nonequilibrium. macroscopic state is per formed in the framework of Informational Statistical Thermodynamics. This i s done in terms of a nonequilibrium Dirac-Landau-Wigner single particle den sity matrix, or, alternatively, in terms of the conjugated intensive nonequ ilibrium. thermodynamic variables. When a local description is not required , the global one can be done by giving the nonequilibrium populations in di e different modes. Also, alternatively, we can introduce a nonequilibrium t emperature (quasi-temperature) per mode, This is compared to a couple of co ntracted descriptions. The evolution of the resulting nonequilibrium thermo dynamic state and the eventual experimental determination are given in the follow-up article. (C) 2001 Elsevier Science B.V. All rights reserved.