Ikuro Sumita

Inner Core Dynamics

This chapter reviews current understanding of the dynamical processes occurring in the inner core, motivated primarily by seismological inferences. First, we present a review of the basics needed for modeling, namely, the physical properties of the iron alloy that constitutes the core, the physics of solidifying alloys, and the grain size and rheology of the inner core. Using these constraints, we review critically the various models that have been proposed to explain seismic velocity, elastic anisotropy, attenuation and attenuation anisotropy, and their radial and lateral variations in the inner core. Finally, we present a review of the models proposed to explain inner core rotation, inferred to exist from the secular changes in seismic velocity in the inner core, and inner core translation, suggested to explain simultaneously lateral variations in the inner core and a layer at the base of the outer core that shows a decrease in the P-wave velocity gradient.

Experiments on highly supercritical thermal convection in a rapidly rotating hemispherical shell

We report experimental results on highly supercritical thermal convection in a rapidly rotating hemispherical shell with parabolic gravity. Using silicone oil as the working fluid and an Ekman number

Experiments on gravitational phase separation of binary immiscible fluids

Ek \,{=}\, 4.7 \,{\times}\, 10^{-6}

Earthquake model experiments in a viscoelastic fluid: A scaling of decreasing magnitudes of earthquakes with depth

we reach Rayleigh numbers up to

Shaking conditions required for flame structure formation in a water-immersed granular medium

1.2 \,{\times}\, 10^{10}

Suspension rheology under oscillatory shear and its geophysical implications

, over 600 times critical. In-situ temperature measurements show that, at these highly supercritical states where convective heat transfer becomes dominant, the time-averaged temperature in the fluid becomes nearly uniform except in a thin thermal boundary layer near the inner spherical boundary. Heat transfer measurements show that Nusselt number

Rotating thermal convection experiments in a hemispherical shell with heterogeneous boundary heat flux: Implications for the Earth's core

\hbox{\it Nu}

Rayleigh‐Taylor instability of a particle packed viscous fluid: Implications for a solidifying magma

increases with Rayleigh number

Thermal Interactions Between the Mantle, Outer and Inner Cores, And The Resulting Structural Evolution of The Core

\hbox{\it Ra}

Experiments on granular rheology: Effects of particle size and fluid viscosity

as