Saha model including volumes of ions

A model of the ionization equilibrium of plasma (the Saha model) is constructed while taking into account the degeneracy of free electrons and the inherent volume of ion cores. The absence of corrections on the charge-particle interaction (the corrections on nonideality) is substantiated. The calculations showed that taking into account the inherent volume of ion cores explains the phenomenon of ionization by compression at high density and taking into account the degeneracy substantially improves the accuracy of thermodynamic functions in this region. All this makes it possible to advance the model of ionization equilibrium far beyond the gas region and extend it into the region of liquid plasma.