STATISTICAL THERMODYNAMICS OF NONIDEAL PLASMA.

Based on the Debye model, the free energy of a nonideal electron-ion plasma is calculated for interaction parameters 0 less than gamma less than gamma //c below the critical solid state value gamma //c ( gamma is the ratio of mean Coulomb interaction energy to thermal energy), which takes into account the energy eigenvalues of (i) the thermal translational particle motions, (ii) the random collective electron and ion motions, and (iii) the static Coulomb interaction energy of the electrons and ions in their oscillatory equilibrium positions. From this physical model, the interaction part of the free energy is derived, which consists of a quasi-lattice energy, depending on the interaction parameter gamma , and the free energies of the quantized electron and ion oscillations (long-range interactions).