Effective Boltzmann law and Prigogine theorem of minimum entropy production in highly charged ion plasmas

Thermodynamics of irreversible processes is applied to study the interaction of matter and radiation field out of thermodynamic equilibrium using a collisional-radiative equilibrium model. We propose to approximate the electronic configuration populations by an effective Boltzmann law. The corresponding effective temperature is obtained by minimizing the rate of entropy production. Numerical calculations for iron plasmas are presented and discussed for up to 100% changes in photon temperature with respect to electron temperature. We found that the notion of effective Boltzmann law combined with the Prigogine theorem of minimum entropy production is very efficient to describe steady-state plasmas far from local thermodynamic equilibrium.