EQUATION OF STATE MEASUREMENTS OF HYDROGEN ISOTOPES ON NOVA

The Nova laser [E. M. Campbell, Laser Part. Beams 9, 209 (1991)] was u sed to shock-compress liquid deuterium and obtain new principal Hugoni ot measurements of density and pressure between 0.3 and 2.1 Mbar. In t his pressure-density region, deuterium is predicted to transform from a molecular insulating fluid to an atomic conducting fluid. Nova data show a rapid increase in density from 0.6 g/cc at 0.3 Mbar, to 1 g/cc at 0.6 Mbar, suggestive of such a transition. The observed sixfold com pression near 1 Mbar is larger than predicted by many widely used equa tion of slate models.