The reduced detailed configuration accounting (RDCA) model for NLTE plasma calculations

The motivation for this work is to provide a more accurate and cost effective in-line NLTE capability for calculating plasma properties in large scale radiation-transport hydrodynamic simulations. A method is developed to transform the large detailed atomic models to very small models that can be used for fast in-line calculations. An averaging technique is used to reduce detailed models involving tens of thousands of states into just a few, 10–40 states, per ionization state. The reduced model is more accurate than the average atom models conventionally used in such simulations. In the present work, the averaging scheme is presented and results of the reduced model are compared to the original detailed model and the average atom model. The average ionization state of iron and uranium plasmas under various conditions of material temperature, atom number density, and radiation temperature are compared.