Development of radiative opacity code OPIND for high energy density plasma and its application in radiation hydrodynamics

Abstract

We developed the program OPIND to generate opacity data for use in radiation hydrodynamics simulations. This is an extension of our earlier work on opacity of elemental plasma based on average atom model [1]. In this work, we extended the capability of OPIND to treat mixture plasmas which employs the ideal gas mixing rule to obtain partial densities. Screened hydrogenic model was employed to obtain radiative properties and hence total opacity. Extensive validation for average ionization and Rosseland mean opacity of C, Al, Fe, Ge, Xe and Au plasmas were performed. OPIND was then employed to study the opacity of CH and Au-Gd mixture plasmas. The role of pressure ionization on CH opacity as well as opacity enhancement in Au-Gd plasma due to the presence of Gd were investigated. Further validation of OPIND was done by performing 1D radiation hydrodynamics simulations to study the ablation in Al slab subjected to radiation temperature drives. We studied the shock trajectory, mass ablation rate and evolution of thermodynamic parameters during shock propagation in Al slab. The scaling law for radiation temperature as a function of shock speed for strong shocks was also verified. We observed good agreement of data generated in our simulations with reported experimental and simulation data. Equation of state data were generated using the SBCRIS library developed by us.