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X-ray Thomson scattering has recently been shown to be an effective method of diagnosing a variety of high energy density plasma conditions. We apply this powerful technique to the widely studied problem of shock-compressed liquid deuterium. The behavior of deuterium under extreme conditions has received considerable attention due to its central role in models of giant planets and the importance of the high-pressure insulator-metal transition. We have used spectrally resolved x-ray scattering from electron-plasma waves to perform microscopic observations of ionization during compression. In these experiments, a single shock was launched in cryogenic deuterium reaching compressions of 3x. The 2 keV Ly-α line in silicon was used as an x-ray source in a forward scattering geometry. In addition to elastic scattering from tightly bound electrons, this low probe energy accessed the collective plasmon oscillations of delocalized electrons. Inelastic scattering from the plasmons allowed accurate measurements of t...

We present scaled demonstrations of backlighter sources, emitting bremsstrahlung x rays with photon energies above 75 keV, that we will use to record x-ray Compton radiographic snapshots of cold dense DT fuel in inertial confinement fusion implosions at the National Ignition Facility (NIF). In experiments performed at the Titan laser facility at Lawrence Livermore National Laboratory, we measured the source size and the bremsstrahlung spectrum as a function of laser intensity and pulse length from solid targets irradiated at 2x10(17)-5x10(18) W/cm(2) using 2-40 ps pulses. Using Au planar foils we achieved source sizes down to 5.5 microm and conversion efficiencies of about 1x10(-13) J/J into x-ray photons with energies in the 75-100 keV spectral range. We can now use these results to design NIF backlighter targets and shielding and to predict Compton radiography performance as a function of the NIF implosion yield and associated background.

We present an instrument platform for studying shock-compressed deuterium on moderately sized laser facilities. The target is designed for cryogenic liquid deuterium to be compressed with a sub-kJ laser pulse. The x-ray probe is the narrow band 2005 eV Si Ly-α resonance produced by a 200 J laser incident on a Si3N4 foil. Scattered x-ray collection occurs in the backward and forward directions; spectral dispersion with Bragg crystals yields the plasma conditions of density and temperature. Additionally, the shock is probed with velocity interferometry. Combined with the electron density measurements from forward scattering, this allows average ionization state to be inferred. Proof of principle experiments demonstrate the viability of this technique for studies of the ionization of deuterium along the Hugoniot.

Summary form only given. Recent principle Hugoniot, pre-compressed Hugoniot, and multiple shock experiments provide equation of state data for several low Z materials including He, H/sub 2/, carbon, and SiO/sub 2/ over an unprecedented pressure-temperature-density regime. We have observed the evolution of these materials from an insulator, to a fluid metal, to a dense plasma, with increasing pressure and density from .5 to 30 Mbar, compression ratios up to 8 fold, and temperatures up to several eV. We present new equation of state and reflectivity data over this P-rho-T range, the inferred high-pressure chemistry, and implications of these data for planetary science.