Ab initio determination on diffusion coefficient and viscosity of FeNi fluid under Earth's core condition.

Abstract

The Earth's outer core is mainly composed of Fe and Ni. The geodynamo of the Earth's core are closely correlated with the transport properties of the fluid in the Earth's core. We selected the typical FeNi fluid, and systemically calculated its diffusion coefficient and viscosity under Earth's core condition by quantum molecular dynamics simulation. The diffusion coefficients are almost constant along the core adiabatic curve. The self-diffusion coefficients of Ni along the core adiabatic curve range from 2.47 × 10-9 to 3.37 × 10-9 m2s-1. The diffusion coefficient increases with temperature increase, while viscosity decrease with temperature increase. The calculations on the transport properties suggest that the Ni impurities have a negligible effect on the diffusion coefficient and viscosity of Earth's core.