POLARIZABILITY OF PARTIALLY-IONIZED, DENSE-PLASMAS (APPLICATION TO PHOTOABSORPTION CALCULATIONS)

A theoretical approach to the polarizability of plasma electrons is pr esented. The formalism takes into account both bound and free electron s. The methods used are: density functional theory for electrons, rand om phase approximation for the response of the electron density and th e cluster expansion in the average over the ion configurations. The fi rst order of the cluster expansion leads to equations for the polariza bility of the average atom. A perturbational approach to this polariza bility is proposed. The theory may be applied to static polarizability which express the variances in the statistical broadening of the aver age atom. A numerical example for gold at 750 eV temperature and solid density is discussed.