Enhancements to ATOMIC to Enable More Options in Modeling XFEL-related Work

Isochoric heating by x-rays in the Kalpha – K edge range of mid-Z elements is of much interest as a method for the creation of large volumes of homogeneous Warm Dense Matter (WDM). WDM is ubiquitous in the Universe (eg planetary interiors) and in laboratory-produced plasmas. Ionization Potential Depression (IPD) is the lowering of the ionization threshold of an ion due to the electrostatic potential from surrounding electrons and neighboring ions. While the Atomic code has historically used the Stewart-Pyatt model in non-LTE calculations, the alternative Ecker-Kroll model has been implemented into the ATOMIC code. These two models will then be assessed by examining the IPD shift of Cu and Fe, with the emphasis on providing higher fidelity modeling capability for experiments that will eventually be executed on the European X-ray Free Electron Laser (XFEL). The planned measurements will record Cu and Fe emission spectra that can be directly compared to the ATOMIC predictions.