Dielectronic recombination in Au ionisation temperature calculations

Abstract

The RADIOM model is designed to supply a radiation-hydrodynamic code with a method that provides non-local thermodynamic equilibrium (NLTE) atomic physics data, by using existing LTE tables, in a manner which is computationally efficient. One of the ingredients is the ionisation temperature, which reproduces the mean ionisation of the plasma. The model does not include dielectronic recombination. We show in the case of Au how this may be remedied by fitting a Gaunt factor to ionisation data derived from off-line NLTE atomic physics codes that take into account two-electron transitions.