Electromagnetic core-mantle coupling for laterally varying mantle conductivity

Nonlinear Core-mantle Coupling

We explore the nonlinear dynamics of a forced core-mantle system. We show that the free axisymmetric motion of a uniform-vorticity Ñuid core coupled to a rigid mantle (the model) is Poincare -Hough integrable. We derive an approximate Hamiltonian for the core tilt mode that includes the leading nonlinear contribution. We then include gravitational perturbations in the analysis. We identify the...

Topographic Core-Mantle coupling in Geodynamo modeling

A 3-dimensional, fully nonlinear numerical geodynamo model is used to study the core-mantle coupling arising from a non-hydrostatic pressure field acting on an aspherical core-mantle boundary (CMB) based on a seismological model. The simulation results demonstrate that the topographic coupling torque is close to being proportional to the square of the amplitude of the CMB topography. We conclud...

Electromagnetic exploration of the oceanic mantle

Electromagnetic exploration is a geophysical method for examining the Earth's interior through observations of natural or artificial electromagnetic field fluctuations. The method has been in practice for more than 70 years, and 40 years ago it was first applied to ocean areas. During the past few decades, there has been noticeable progress in the methods of instrumentation, data acquisition (o...

Scanning for Velocity Anomalies in the Crust and Mantle with Diffractions from the Core-Mantle Boundary

Silicon Mantle/core Fractionation and the Origin

Experimentally determined metal/olivine partition coefficients and diffusion rates will help answer questions relating to Earth's elevated Mg/Si ratio and will provide better tools for the determination of the origin of pallasites. It is known that the Mg/Si ratio of the Earth's primitive upper mantle (PUM) is elevated relative to all types of chondrites (possibly not CV chondrites), Mars, and ...