Viscosity of Fluids in the Diamond Anvil Cell

Measurement and modelling of the viscosity of fluids under high pressures is necessary to an understanding of fluid processes within Earth and other planets. We report some of our first results of rolling ball viscometry within the diamond anvil cell, which technique allows measurements in regimes of density higher than those where Enskog theory is satisfactory. Several simple fluids are compared in terms of reduced parameters and free-volume theory. Potentials of the technique are discussed.