Experimental observation of nonlocal electron transport in warm dense matter*

We present the first experimental observation of electron transport in warm dense matter using X-ray Thomson Scattering (XRTS) measurement from low-density CH foams compressed by a strong laser-driven shock at the OMEGA laser facility [1]. The XRTS measurement was combined with VISAR and optical pyrometry (SOP) providing a robust measurement of thermodynamic conditions in the shock. Evidence of significant preheat contributing to elevated temperatures reaching 17.5-35 eV in shocked CH foam was measured by XRTS. These measurements were complemented by abnormally high shock velocities observed by VISAR and early emission seen by SOP. These results were compared to radiation hydrodynamics simulations that include first-principles treatment of nonlocal electron transport in WDM with excellent agreement.

[1] K. Falk et al., Phys. Rev. Lett. 120, 025002 (2018).