Laser-driven shock experiments on precompressed water: Implications for "icy" giant planets.

ABSTRACT

Laser-driven shock compression of samples precompressed to 1 GPa produces high-pressure-temperature conditions inducing two significant changes in the optical properties of water the onset of opacity followed by enhanced reflectivity in the initially transparent water. The onset of reflectivity at infrared wavelengths can be interpreted as a semiconductor<-->electronic conductor transition in water, and is found at pressures above approximately 130 GPa for single-shocked samples precompressed to 1 GPa. Our results indicate that conductivity in the deep interior of "icy" giant planets is greater than realized previously because of an additional contribution from electrons.