Viscosity measurements in liquid iron and iron sulfides at high pressures and the calculation of the Earth's core viscosity

摘要

Recent experimental and calculated data on the viscosity of liquid iron and its compounds at high pressures are reviewed. These results are at variance with data obtained by Brazhkin and Lyapin, in particular, with their conclusion on a significant increase in the iron viscosity under conditions of the Earth's outer core based on their universal law of a regular viscosity variation along the metal melting curve. Available experimental data on the viscosity measured in shock wave compression experiments at a few megabars are considered. Specific features of the iron phase diagram including phase transitions are shown to hinder the extrapolation of viscosities measured at 100-200 kbar into the range of higher pressures typical of the Earth's core.