Correlated quantum screening model for non-ideal plasmas

For an ion embedded in dense plasma, the electron screening will greatly alter its atomic properties and leads to the various phenomena, such as ionization potential depression (IPD) and line shift etc. An accurate description of electron screening effect is of crucial importance in the simulations of radiation transport and Equation of State in dense plasmas. In the present work, an electron screening model considering electron correlation and quantum degeneracy effects is proposed for treating non-ideal plasma. In this model, the Fermi-Dirac distribution is modified to include the electron correlation effect, and plasma electrons are assumed be able to occupy the bound orbitals (with negative energy) of an embedded ion. When investigating the screening effect on a specific bound state of the embedded ion, the quantum degeneracy between negative-energy electrons and the studied bound state is considered and leads to a dependence of the plasma-electron distribution on the specific bound state. The model is applied to calculate line shifts of He-like ion embedded in non-ideal plasma and much better agreements with the latest two experimental results are achieved in comparison with other screening models' calculations.