Molecular dynamic studies on materials under laser shocks

Abstract

Molecular dynamic (MD) simulations offer a powerful means of understanding the microscopic characteristics of shock-propagation through solids and fluids, especially for the short spatial and temporal scales relevant to laser-driven shocks. First-principles molecular dynamics can be directly compared with time-resolved experimental measurements, and methods based on empirical (embedded-atom) potentials fitted to first-principles quantum-mechanical calculations are effective for MD simulations of shock propagation through many millions of atoms. In comparison, thermodynamic approaches based on free-energy considerations do not provide detailed information about mechanical-relaxation or phase-transformation processes within the shock front. We illustrate these ideas by way of embedded-atom simulations of shock-wave propagation through copper crystals of different orientation.