<< The dynamical processes of the inner core rely significantly on the viscous strength of iron. Since plastic deformation of iron may produce crystallographic preferred orientations (CPO), creep is commonly considered to be a potential source contributing to the seismic anisotropy observed in the inner core. The viscosity of the inner core also influences the rotational dynamics of the Earth. >>
AA << show that dislocation creep is a key mechanism driving deformation of hcp (hexagonal close packed) iron at inner core conditions. The associated viscosity agrees well with the estimates from geophysical observations supporting that the inner core is significantly less viscous than the Earth’s mantle. Such low viscosity rules out inner core translation, with melting on one side and solidification on the opposite, but allows for the occurrence of the seismically observed fluctuations in inner core differential rotation. >>
Sebastian Ritterbex & Taku Tsuchiya. Viscosity of hcp iron at Earth’s inner core conditions from density functional theory. Sci Rep 10, 6311 (2020). doi: 10.1038/s41598-020-63166-6. Apr 14, 2020.
https://www.nature.com/articles/s41598-020-63166-6
Is the Earth's inner core oscillating and translating anomalously? Ehime University. Apr 14, 2020.
https://phys.org/news/2020-04-earth-core-oscillating-anomalously.html
