Effect of Ionic Disorder on the Principal Shock Hugoniot

TL;DR

This paper investigates how ionic disorder influences the principal shock Hugoniot at extremely high pressures, revealing its significance mainly during initial shell ionization stages, with effects diminishing at higher pressures due to increased electron ionization.

Contribution

It introduces a comparative analysis of ionic disorder effects using molecular dynamics and Multiple Scattering Theory at Gbar pressures for carbon and aluminum.

Findings

Ionic disorder significantly affects the Hugoniot at shell ionization onset.

At higher pressures, ionic environment effects are overshadowed by ionized electrons.

Disorder effects are most critical at initial ionization stages.

Abstract

The effect of ionic disorder on the principal Hugoniot is investigated using Multiple Scattering Theory to very high pressure (Gbar). Calculations using molecular dynamics to simulate ionic disorder, are compared to those with a fixed crystal lattice, for both carbon and aluminum. For the range of conditions considered here, we find that ionic disorder is most important at the onset of shell ionization and that at higher pressures, the subtle effect of the ionic environment is overwhelmed by the larger number of ionized electrons with higher thermal energies.