Refractive index and elastic properties of z-cut quartz shocked to 60 kbar

Shock wave experiments were performed to characterize z-cut, alpha -quartz as an optical window for velocity interferometry measurements. Refractive index changes and shock velocities were determined to 60 kbar peak stress. Results indicate that the window correction to velocity measurements is a constant fraction of the actual particle velocity, Deltau/u=0.081 07. Shock velocity measurements provide the Hugoniot curve to 60 kbar, and yield the fourth-order elastic constant, C-3333=174 810 kbar. By combining the velocity correction factor and the shock velocity measurements, the refractive index is determined to be a linear function of density. This finding is used to show that the velocity correction appropriate for a step jump may be applied to monotonically time-dependent wave forms with negligible error. The present work has demonstrated the use of z-cut quartz as an optical window to 60 kbar. (C) 2000 American Institute of Physics. [S0021-8979(00)02023-5].