Dynamic Compression of Hydrogen and Other
Small Molecular Fluids at High Pressures
Dynamic compression of molecular
fluids using both single-shock (Hugoniot) and multiple-shock compression
achieves pressures which range up to several Mbar (100 GPa), compressions up to
ten-fold of ambient liquid density, and temperatures up to several 1000 K in
degenerate condensed matter. For
several diatomic fluids, nonmetal-metal transitions determined by electrical
conductivity measurements at densities achieved by multiple-shock compression
and pressure-volume Hugoniot curves each have universal systematic
behaviors. The extreme conditions are
achieved for ~ 100 ns using a two-stage light-gas gun, which accelerates a 20-g
projectile to kinetic energies as high as 0.5 MJ. The systematics will be discussed, including the nonmetal-metal
transition in fluid hydrogen at 1.4 Mbar and 10-fold compression and the controversial
issue of the pressure-volume Hugoniot curve of deuterium near 100 GPa and
4-fold compression.