On the robustness of DFT–Kubo–Greenwood DC conductivity in warm dense matter

Pacific Fusion is developing an 80 MJ pulsed-power Demonstration System designed to deliver 60 MA to an inertial confinement fusion (ICF) target in ~100 ns, with the goal of achieving net facility gain. Predictive magnetohydrodynamics (MHD) simulations of these magnetically driven implosions require accurate, tabulated DC electrical conductivities over wide density-temperature ranges.

Density-functional theory with the Kubo-Greenwood formula (DFT-KG) is a leading first-principles approach for calculating DC conductivity, particularly in the warm dense matter (WDM) regime where experimental measurements are scarce. However, the predicted DC conductivities can depend strongly on choices including, but not limited to, the specific KG expression and the functional form/width of the spectral-broadening delta function. We present a systematic study of these sensitivities for materials in WDM conditions and identify the strategies that mitigate variability in the predicted DC conductivity. We further compare against time-dependent DFT (TDDFT), with and without Ehrenfest dynamics, to assess local-field effects and other physical processes not explicitly captured in standard DFT-KG calculations. The resulting guidance supports the generation of precise conductivity tables for MHD codes modeling magnetically driven ICF.