Experimental configuration for isentropic compression of solids using pulsed magnetic loading

Abstract

A capability to produce quasi-isentropic compression of solids using pulsed magnetic loading on the Z accelerator has recently been developed and demonstrated [C. A. Hall, Phys. Plasmas 7, 2069 (2000)]. This technique allows planar, continuous compression of materials to stresses approaching 1.5 Mbar. In initial stages of development, the experimental configuration used a magnetically loaded material cup or disk as the sample of interest pressed into a conductor. This installation caused distortions that limited the ability to attach interferometer windows or other materials to the rear of the sample. In addition, magnetic pressure was not completely uniform over sample dimensions of interest. A new modular configuration is described that improves the uniformity of loading over the sample surface, allows materials to be easily attached to the magnetically loaded sample, and improves the quality of data obtained. Electromagnetic simulations of the magnetic field uniformity for this new configuration will also be presented. Comparisons between data on copper to ∼300 kbar using the old and new experimental configurations will also be made. Results indicate that to within experimental error, the configurations produce similar results in the pressure-volume plane.

Near-equilibrium polymorphic phase transformations in praseodymium under dynamic compression

“…A wealth of static high pressure studies have engaged a range of techniques to map the material behavior under compression. While early experimental studies focused on static pressure conditions [5][6][7][8][9] or nearlyinstantaneous shock loading conditions [10], recent developments have enabled explorations on intermediate timescales [11][12][13].…”

High pressure phase transformation in iron under fast compression

“…Following an electro-magnetic pulse (see Ref. [26] for details of the pulse generation) the Al anode compresses uniaxially the iron sample. We monitored the motion of the boundary between the iron and the transparent Al 2 O 3 window (henceforth designated as boundary) as the compression wave propagated through the sample -see Fig.…”

New Experimental Capabilities and Theoretical Insights of High Pressure Compression Waves

“…We present here very recent observations that span the three RWC drive platforms: light-gas gun [1], magnetic flux [2], and laser [3]. However, first lets state the obvious in that RWC is inherently nonlinear due to the sound speed depending upon the density and therefore causing the high-pressure states in the compression wave to travel faster than .…”

“…The fruition of three primary platforms (light-gas gun [1], magnetic-flux [2], and laser [3]) to apply high pressure ramp impulses to subject materials has dawned and promises to lead us to new discoveries and to help our understanding of material response at pressures approaching our sun's interior [4]. The initial efforts of ramp-wave compression(RWC) have their origin in World War II and was made more public in the 1960's (see Fowler [5]); however, not until 1970 did the first magnetic-flux experiments on hydrogen take place obtaining ∼ 2 Mbar, albeit these experiments lacked support material knowledge and adequate diagnostics [6].…”