Use of fast pulsed power for high-pressure equation-of-state studies

Abstract

Summary form only given. Recent developments in fast pulsed power have enabled an innovative approach for obtaining accurate high-pressure equation-of-state (EOS) data. The new method, referred to as the Isentropic Compression Experiment (ICE), uses the large currents produced over time intervals of 200-300 ns on the Z Accelerator to perform EOS experiments. Sample configurations have been developed on the accelerator to continuously load planar specimens with a magnetic field to peak pressures exceeding 200 GPa (2 Mbar). Time-resolved velocity measurements performed on the specimen are then used to extract EOS data along a material path that is quasiisentropic. The ability to perform quasi-isentropic EOS experiments over this pressure range has been a goal of the shock wave community for several years because these measurements provide unique EOS data previously unavailable. This loading condition is also useful for studying other physical effects, such as pressure-induced phase transitions or compressive material strength that are not easily studied with other methods. The ICE technique represents a major advance in shock physics and has opened a new sub-field of high-pressure research. This paper will review development of the ICE technique, including use of MHD codes to design and analyze ICE and flyer plate experiments. Several recent examples will be presented to illustrate the versatility of the method. Finally, prospects for increasing peak pressures and flyer plate velocities achievable with the technique will be discussed.