Analysis and modeling of laser ramps and shocks in tiitatium and zirconium with phase transitions

Abstract

Using temporal pulse shaping, laser ablation can generate shocks or ramp loading in samples. Shock data can often be analyzed using analytic calculations, but integrated calculations are required in the case of ramps.When phase transitions occur, surface velocity historiesmay become much more complicated, requiring accurate hydrocode simulations for interpretation. The shock may be split by phase transitions and the slope of the ramp interacts with phase transition kinetics. The analysis of these experiments requires a good knowledge of phase transition thermodynamics i.e. an accurate multiphase equation of state (EOS). Recently, laser experiments have been performed on samples exhibiting phase transitions, complemented by a general model of multiphase EOS developed at CEA. The aim of the present study was to compare equilibrium multiphase EOS with qualitative and quantitative features of the experimental data. Multiphase EOS were constructed for Ti and Zr using static data. Good agreement was found between most experiments and calculations, demonstrating the accuracy of the multiphase EOS. In some cases, the experimental data show obvious kinetic effects. © 2012 American Institute of Physics.