Temperature and density measurements from stellar interior oxygen opacity experiments using K-shell spectroscopy

Our understanding of material opacities in stellar interiors is under scrutiny.  Oxygen is among the important contributors to opacity near the base of the solar convection zone.  Remarkably, the conditions in this region (180eV, 1e23 e/cc) are similar to some white dwarf stars.  The experimental platforms at Z and NIF previously used to study iron opacities also allow for the study of oxygen at these conditions.  Measurements of the oxygen opacity have been carried out using SiO2 samples on each platform.  For proper comparison of the experimental oxygen opacities with theoretical models, the conditions of the experimental plasma must be well known.  In this talk, we will be discussing the methods used to measure the temperature and density of the samples via Si K-shell absorption spectroscopy.

This work was supported in part by the Wootton Center for Astrophysical Plasma Properties under U.S. DOE cooperative agreement number DE-NA0003843.  SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.