Measuring Viscosity in Materials At High Pressure and High Temperature

A material’s viscosity, or resistance to flow, is highly dependent on its thermodynamic conditions. Little is understood about the viscosity of systems under warm dense matter conditions (pressures above 100 GPa), as there are no viscosity measurements taken at pressures above 25 GPa and temperatures above 3000 K. We are developing an experimental platform to obtain viscosity measurements for materials under warm dense matter conditions through utilizing the viscous effect on the evolution of a sinusoidal shock front travelling through a planar target. We have preliminary viscosity measurements for both SiO2 and diamond at pressures above 500 GPa using this platform.