Atomic process modeling in dense hydrogenic plasmas by nearest neighbor approximation

Atomic process modelling for obtaining the electronic state densities of the bound and free electrons and calculating the resulting average ionization degrees of dense hydrogenic plasmas is studied. In the analysis of atomic processes in plasmas, the Saha equation is usually solved to obtain population of each ionic species of various electronic configurations and resulting average ionization degrees as a function of electron temperature and plasma density under the assumption that the plasmas are in a certain equilibrium, for example, the thermodynamic equilibrium. I had proposed an atomic model based on the nearest neighbor approximation to determine a finite state density of the bound state and a state density of the free electron in hydrogenic plasmas. Using the models, we had been able to calculate the population for ions of various electronic configurations in hydrogenic plasmas without any ad hoc parameters to determine the electronic state densities. Unfortunately, the models had not been able to apply for dense plasmas near solid density. In this paper, examining the effect of the Coulomb interaction between the two ions and the Saha equation, we discuss the applicability of the models for dense hydrogenic plasmas.