Pierre Noiret

Electrical conductivity of a strongly correlated aluminium plasma

We present theoretical estimations of the electrical conductivity of a warm expanded aluminium plasma (ρ = 0.3 g cm−3). Our calculations are carried out in the framework of density functional theory and the local density approximation. Ionic configurations were determined by ab initio molecular dynamics simulations, from which the conductivity was computed using the Kubo–Greenwood formula. Theoretical results were validated in the dense coupled regime (ρ = 2 g cm−3) against previously published experimental results. For the low-density regime, the result is compared to experiments obtained in our laboratory in an isochoric closed-vessel designed to confine electrical plasma discharges up to 1.5 GPa. In this regime we show that the usual Drude model is no longer relevant and that the electrical conductivity is driven by the optical properties.

Experiments and simulations on Al-Au mixtures and mixtures laws

We measured the thermodynamical and transport properties of aluminum-gold mixtures in the warm dense matter regime and for various concentrations. We compare these measurements with quantum molecular dynamics (QMD) simulations. We find that the calculated pressures and resistivities of both the mixtures and pure phases are in good agreement with the measurements. This further allows us to test the mixing rules usually employed to predict the properties of the mixed phases from the pure ones. We show, in this regime, that the partial densities mixing rule predicts the pressure of the mixture rather accurately but fails in its prediction of the optical conductivity. To improve this latter prediction, we find that we must invoke an isothermal-isobaric mixture rule to compute the pure phase contributions at the correct densities.