Isentropic compression of metals, at multi-megabar pressures, using high explosive pulsed power

Accurate, ultra-high pressure isentropic equation of state (EOS) data, are required for a variety of applications and materials. Asay (1999) reported a new method to obtain these data using pulsed magnetic loading on the Sandia Z-machine. Fast rising current pulses (risetimes from 100 to 300 ns) at current densities exceeding many MA/cm, create continuous magnetic loading up to a few Mbar. As part of a collaborative effort between the Los Alamos and Lawrence Livermore National Laboratories, the authors are adapting their high explosive pulsed power (HEPP) methods to obtain isentropic EOS data with the Asay technique. This year, they plan to obtain isentropic EOS data for copper and tantalum at pressures up to /spl sim/2 Mbar; eventually we hope to reach several tens of Mbar. They describe the design of the HEPP systems and show their attempts to obtain EOS data to date.