Probing thermal transport in dynamically-compressed materials using Cu Extended X-ray Absorption Fine Structure*

While determining temperature in laser-driven material science platform remain challenging and is a major source of uncertainty in equation-of-state experiments, recent experiments using Extended X-ray Absorption Fine Structure (EXAFS) as a temperature diagnostic have shown great promise and also provided new insights into thermal transport in planar dynamic-compression targets. We discuss in this work the temperature of Cu dynamically compressed to 400 GPa determined using EXAFS at the National Ignition Facility, and how this temperature varies depending on the material adjacent to the Cu. The observed sensitivity to Cu thickness and the significantly higher temperature in Cu when adjacent to diamond suggest that thermal conduction plays an important role in the measured Cu temperature over the experiment timescale, and that the diamond temperature is higher than predicted by radiation-hydrodynamic simulations.