Low Pressure Shock Hugoniot of Silica Aerogel

We present measurements on the low pressure shock Hugoniot of silica aerogel. Previous measurements of the shock Hugoniot of silica aerogel give a Hugoniot that when extrapolated to lo pressures give unphysical results. In this study, we used photonic Doppler velocimetry to measure the shock transit time in silica aerogel. The new shock Hugoniot data show a turnover in the shock Hugoniot of silica aerogel at low pressures. The turnover resolves the unphysical behavior in the shock Hugoniot. \\\\ This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.