Measurement of the compressibility of a deuterium plasma at a pressure of 1800 GPa

Isentropic compression of hydrogen: Probing conditions deep in planetary interiors

“…An extension of the experiment of Fortov et al towards a much higher compression ratio of ρ/ρ 0 ∼ 108 has been performed by Mochalov et al 14 They started from the same gaseous initial state of deuterium as in Ref. 13.…”

“…Quasi-isentropic shock wave experiments using high explosives were performed recently to study the nonmetal-tometal transition in hydrogen and deuterium, 13 the behavior of hydrogen at pressures up to about 18 Mbar, 14 and the highpressure cold curve of hydrogen and deuterium. 15 The sample in each experiment was compressed by high explosives using cylindrical or spherical symmetry.…”

“…States off the principal Hugoniot curve can be investigated by varying the initial conditions via solid or gaseous targets, 10,11 applying reverberating shock waves, 7,8,12 or using isentropic compression that generates high pressures at moderate temperatures. [13][14][15] Isentropic compression also probes conditions along a planetary isentrope if the initial conditions are chosen appropriately. This would allow us to discriminate between competing planetary interior models.…”

Isentropic Compression of Deuterium by Quantum Molecular Dynamics

“…Recently the compression isentrope of deuterium has been measured [10,11] with the evidence of 20% density jump at pressure P ≈ 130 GPa. In these experiments a cylindrical [10] or spherical [11] loading devices were used. Deuterium was placed between two aluminum shells; the density of deuterium was determined by means of γdetectors, the pressure was calculated with the help of hydrodynamic simulation.…”

“…Probably the most intriguing problem in hydrogen-like systems is the possible existence of the plasma phase transition [6,7] and dissociation-driven phase transition [8,9]. Recently the compression isentrope of deuterium has been measured [10,11] with the evidence of 20% density jump at pressure P ≈ 130 GPa. In these experiments a cylindrical [10] or spherical [11] loading devices were used.…”