Experimental studies of thermal conductivity in warm dense iron

We present the first experimental thermal conductivity studies of warm dense iron at 0.5-7.8 g/cc and 3-5 eV. The experiment used 6.8 keV x-rays from the LCLS XFEL to volumetrically heat thin bi-layer Au/Fe targets and establish a prompt temperature gradient at the layer interface. Time-resolved diagnostics measure both the thermal self-emission at the target rear surface and the expansion velocity. Data is modeled with a 1D two-temperature hydrodynamics calculation in Hydra. The results are sensitive to EOS, optical opacity, and thermal conductivity; the relative impacts of models for each category will be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 with support from DOE OFES Early Career program.