[en] The summary of the report is: (1) We have proposed, used, and validated (using aerogel and D₂) quartz as an impedance-match standard; (2) We have collected extensive EOS data on He, D₂, and H₂ at conditions relevant to giant planet interiors; (3) We observe relatively soft EOS's for all three materials; (4) We observe temperature-induced ionization in He (5) Our analysis indicates a strong electronic-gap density dependence; and (6) Our results favor planetary models for Jupiter that include partitioning of heavy elements into a relatively large core.

No abstract available

[en] The compression η of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that η ≅ 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa η reaches a maximum of ∼5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa

[en] High precision laser-driven shock wave measurements of the diamond principal Hugoniot have been made at pressures between 6 and 19 Mbar. Shock velocities were determined with 0.3-1.1% precision using a velocity interferometer. Impedance matching analysis, incorporating systematic errors in the equation-of-state of the quartz standard, was used to determine the Hugoniot with 1.2-2.7% precision in density. The results are in good agreement with published ab initio calculations which predict a small negative melt slope along the Hugoniot, but disagree with previous laser-driven shock wave experiments which had observed a large density increase in the melt region. In the extensive solid-liquid coexistence regime between 6 and 10 Mbar these measurements indicate that the mixed phase may be slightly more dense than would be expected from a simple interpolation between liquid and solid Hugoniots

[en] Temperatures measured on the shock-Hugoniot of diamond reveal melting between 650 (± 60) GPa and 9000 (± 800) K and 1090 (± 50) GPa and 8400 (± 800) K, with a heat of fusion of ∼ 25 ± 10 kJ/mole and a negative Clapeyron slope ∂T/∂P|_melt = -5 ± 3 K/GPa. Thus, the fluid is denser than the compressed solid, and optical reflectivity measurements show it to be metallic. Hugoniot-temperature measurements extending to over 4000 GPa (40 Mbar) and 115,000 K suggest de-polymerization of a dense covalently-bonded fluid to an atomic state between 10,000 and 30,000 K. These experimental results indicate that carbon present deep inside planets such as Uranus and Neptune could be solid for through-going convection, whereas stable stratification would allow for the presence of fluid metallic carbon at depth; in either case, the presence of carbon could potentially affect planetary seismic normal modes.

[en] We demonstrate the recently developed technique of laser driven isentropic compression (ICE) for dynamically compressing Al samples at high loading rates close to the room temperature isentrope and up to peak stresses above 100GPa. Upon analysis of the unloading profiles from a multi-stepped Al/LiF target a continuous path through Stress-Density space may be calculated. For materials with phase transformations ramp compression techniques reveals the location of equilibrium phase boundaries and provide information on the kinetics of the lattice re-ordering

[en] Most single-crystal shock experiments have been performed in high-symmetry directions while the nature of shock propagation in low-symmetry directions remains relatively unstudied. It is well known that small-amplitude, linear acoustic waves propagating in low-symmetry directions can focus and/or form caustics (Wolfe, 1995). In this report we provide evidence for similar focusing behavior in nonlinear (shock) waves propagating in single crystals of silicon and diamond. Using intense lasers, we have driven non-planar (divergent geometry) shock waves through single-crystals of silicon or diamond and into an isotropic backing plate. On recovery of the backing plates we observe a depression showing evidence of anisotropic plastic strain with well-defined crystallographic registration. We observe 4-, 2-, and 3-fold symmetric impressions for [100], [110], and [111] oriented crystals respectively

[en] The knowledge of the equations of state of helium and hydrogen in high temperature and high density ranges is necessary to design inertial fusion targets adequately. The experimental assessment of the relationship that links volume, pressure, energy, temperature and ionization in this thermodynamic domain is a real challenge. We have developed a new technique that combines static compression and dynamical compression. It is based on the generation of laser shocks in diamond anvil cells. This paper illustrates the application of the method to helium via the warm dense matter (WDM) technique that is well adapted to highly compressible fluids. It appears that the WDM technique needs to be refined. (A.C.)

[en] An accurate equation of state (EOS) for planetary constituents at extreme conditions is the key to any credible model of planets or low mass stars. However, very few materials have their high pressure (>few Mbar) EOS experimentally validated, and even then, only on the principal Hugoniot. For planetary and stellar interiors, compression occurs from gravitational force so that material states follow a line of isotropic compression (ignoring phase separation) to ultra-high densities. An example of the hydrogen phase space composing Jupiter and one particular Brown Dwarf is shown. At extreme densities, material states are predicted to have quite unearthly properties such as high temperature superconductivity and low temperature fusion. High density experiments on Earth are achieved with either static compression techniques (i.e. diamond anvil cells) or dynamic compression techniques using large laser facilities, gas guns, or explosives. The ultimate goal of this multi-directorate and multi-institutional proposal was to develop techniques that will enable us to understand material states that previously only existed at the core of giant planets, stars, or speculative theories. Our effort was a complete success, meeting all of the objectives set out in our proposals. First we focused on developing accurate Hugoniot techniques to be used for constraining the equation of state at high pressure/temperature. We mapped out an accurate water EOS and measured that the ionic->electronic conduction transition occurs at lower pressures than models predict. These data and their impact are fully described in the first enclosed paper ''The Equation of State and Optical Properties of Water Compressed by Strong Shock Waves.'' Currently models used to construct planetary isentropes are constrained by only the planet radius, outer atmospheric spectroscopy, and space probe gravitational moment and magnetic field data. Thus these data, which provide rigid constraints to these models, will have a significant impact on a broad community of planetary and condensed matter scientists, as well as our fundamental understanding of the giant planets. We then developed and tested precompressed and multiple shock techniques on water. Scientists around the world have teamed with us to conduct these complex and seminal high density experiments which allow access to the extreme core states of giant plants. Double shock experiments using a variety of anvils to compress water to densities higher and temperatures lower than accessible by single shock Hugoniot techniques. First a clear determination of the EOS and optical properties of the anvils needed to be measured. These properties for LiF and A1203 are written up in the second attached article, ''Shock-Induced Transformation of Sapphire and Lithium Fluoride into Semiconducting Liquids.'' An example double shock data record for water is shown. This data is being written up for publication

[en] A goal of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is to better understand solid matter behavior at extreme conditions. Diagnostic tools such as the Target Diffraction In-Situ (TARDIS) have been designed to record data of solid material compressed to tens of Mbars over short time scales. NIF drive beams (∼120 kJ) heat a carefully designed ablator to ramp compress the target to high pressure. A backlighter produces an x-ray source which is diffracted onto image plates through the compressed target. An unimpeded optical path allows Velocity Interferometer System for Any Reflector (VISAR) measurements to be recorded as the compression wave progresses through the target. To reduce the VISAR blast shield's exposure to debris and minimize contamination of the NIF chamber, a transparent barrier has been designed to contain debris within the TARDIS body. (paper)