An advanced theory of Stark broadening for diagnostics of dense plasmas

There exist various models describing spectral line broadening for multicharged ions in dense plasmas. However, a significant ambiguity still remains being manifested as drastic discrepancies between line profiles (LP) calculated by different groups. To improve the situation the authors developed the following advanced model. A mean time τe of plasma electron relaxation to a local equilibrium, a radiational decay time τr of an excited state of a radiator and a characteristic time τi of varying of the ion microfield usually obey a relationship τe << τr << τi. A number of plasma electrons simultaneously interacting with a radiating ion is greater than unity. So plasma electrons may be treated as a canonical ensemble in a bulk plasma thermostat. They are considered in a state of local thermodynamical equilibrium under fixed states of bound electrons and a random configuration of plasma ions. While calculating a nonlinear screening of bound states and an ion-ion pair potential they use a two-centered model where plasma electrons belonging to two selected ions are separated from the bulk plasma electrons by a boundary. An energy of a radiative transition is calculated as a difference of free energies of this ensemble with bound electrons in excited and ground states respectively. To describe bound states and a free electrons distribution they utilize the Density Functional Theory (DFT) for finite temperatures. Bound state occupation numbers are fixed and correspond to the radiative transition under consideration. Plasma temperature is high enough for nondegeneracy of free electrons, so that they treat them in the quasiclassical approximation. They use the Local Density Approximation for finite temperatures to describe an exchange and correlations between electrons by some local potential