Experimental and computational investigation of the shock melting properties of diamond*

The shock melting of diamond has gained interest of late due to its possible use as an ablator material in inertial confinement fusion capsules. Recently, experiments utilizing the flyer plate capability at the Sandia Z accelerator were performed to determine the Hugoniot and the shock melting properties of polycrystalline diamond. Composite aluminum/copper flyer plates were used to shock load diamond samples to pressures ranging from 5 to 14 Mbar. Multiple samples and fast diagnostics provided Hugoniot measurements with roughly 1 percent accuracy in density. Furthermore, measurements of the release behavior may provide direct indication of the extent of the coexistence region on the Hugoniot. These high precision Hugoniot and release measurements at multi-Mbar pressures allow for high fidelity comparisons with recent quantum molecular dynamics calculations, and provide insight into the shock melting of diamond.