Backward and Forward Analyses of Shocked and Ramp-Compressed Metals to 5 Mbars*

In this report, we present a series of shocked and ramp compressed data on various metals including tantalum and tin. These samples were shocked and ramp-compressed to pressures as high as 5 Mbars with graded density impactors (GDI). To analyze these data, we utilize both backward (characteristics) and forward analyses. The former method does not require a priori knowledge of a pressure drive, and often fails in the presence of strength or phase transition. By using both of these analysis techniques, we can explore the possibility of looking at phase transition and strength during ramp compression. This study also gives us insight into the in-situ properties of GDI during ramp compression. The results are compared to non-destructive ultra sound scans of GDIs.