Implementation of Non-Equilibrium Equation-of-State Model in Radiation-Hydrodynamics Code HELIOS-CR

HELIOS-CR is a 1-D radiation-magnetohydrodynamics code that is used to simulate the dynamic evolution of plasmas created in high energy density physics (HEDP) experiments. Radiative and atomic processes in plasmas play a critical role in a wide variety of such experiments. We will discuss a new model that accounts for the effect that collisional-radiative atomic kinetics may play on the equation-of-state (EOS) and on overall plasma evolution. In the implementation of EOS models affected by collisional-radiative kinetics, we closely follow the formalism developed at LLNL (H.A. Scott, Chapter 4 in Modern Methods in Collisional-Radiative Modeling of Plasmas", Vol 90 (2016)). We will present the details of the newly developed model and discuss the simulation results for typical applications where the non-equilibrium atomic kinetics is expected to be important, e.g., for photoionized plasmas.