Comprehensive Comparison of VISAR and PDV Laser Interferometry in Plane Shock Wave Experiments

Plate impact experiments, using well-characterized materials, were conducted to achieve a direct and comprehensive comparison of two laser interferometry approaches used to measure shock wave profiles: Velocity Interferometer System for Any Reflector (VISAR) and Photon Doppler Velocimetry (PDV). A unique feature of this study was a one-to-one comparison of the two measurement approaches in each experiment. A broad range of stresses (4-60 GPa) were examined in this study. The choice of impactor and target materials permitted us to examine different types of material responses (elastic, elastic-plastic, and time-dependent elastic-plastic deformation) which, in turn, resulted in different types of wave profiles (single wave, two-wave structure, and two-wave structure with rapid stress relaxation following the first wave). Overall, the two approaches showed good agreement. However, small but discernible differences were observed in the following situations: wave profiles involving rapid stress relaxation behind the elastic wave; and window-corrected, peak states at high stress. The relative strengths and weaknesses of both methods are summarized. Work supported by DOE/NNSA.