Reflected Shock Experiments on the Equation-of-State Properties of Liquid Deuterium at 100–600 GPa (1–6 Mbar)

Abstract

New laser-driven shock experiments have been used to study the equation-of-state (EOS) properties of liquid deuterium. Reflected shocks are utilized to increase the shock pressure and to enhance the sensitivity to differences in compressibility. The results of these experiments differ substantially from the predictions of the Sesame EOS. EOS models showing large dissociation effects with much greater compressibility (up to a factor of 2) agree with the data. By use of independent techniques, this experiment offers the first confirmation of an earlier observation of enhanced compressibility in liquid deuterium.

Equations of state for hydrogen and deuterium.

“…Those experiments gave shock compressions as much as 45% higher than predicted by the 1972 EOS. Later experiments using the Nike laser at the Naval Research Laboratory gave similar results 1311 [32]. Many papers have since appeared to offer explanations for the discrepancy and models that are in better agreement with the laser data.…”

“…We believe it is now clear that the Nova/Nike laser data in Refs. [28]- [32] either contain systematic errors or nonequilibrium effects that have not yet been identified. We will proceed on that assumption in the present work.…”

Physics of Substellar Objects Interiors, Atmospheres, Evolution

“…The reflectivity of shocked deuterium reaches about 60% for pressures above 0.5 Mbar along the Hugoniot (Celliers et al 2000), a value indicative of a large density of free electrons and of a high electric conductivity characteristic of fluid metallic hydrogen. Second-shock compression up to 6 Mbar with the Nike laser give results in agreement with the NOVA (P, ρ) data (Mostovych et al 2000). On the other hand, Knudson et al (2001) used a magnetic Z-accelerator to accelerate impactors to very high velocities.…”

Laser-shock compression and Hugoniot measurements of liquid hydrogen to 55 GPa

“…For this reason, most of the recent experimental measurements by shock compression have focused on the heavier isotope [11][12][13][14][15][16] . However, it should be noted that the Hugoniots for the two isotopes do not scale in density.…”