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arXiv · 2101.01493

Fast Quasi-Geostrophic Magneto-Coriolis Modes in the Earth's core

Felix Gerick·Dominique Jault·Jerome Noir
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Abstract

Fast changes of Earth's magnetic field could be explained by inviscid and diffusion-less quasi-geostrophic (QG) Magneto-Coriolis modes. We present a hybrid QG model with columnar flows and three-dimensional magnetic fields and find modes with periods of a few years at parameters relevant to Earth's core. For the simple poloidal magnetic field that we consider here they show a localization of kinetic and magnetic energy in the equatorial region. This concentration of energy near the equator and the high frequency make them a plausible mechanism to explain similar features observed in recent geomagnetic field observations. Our model potentially opens a way to probe the otherwise inaccessible magnetic field structure in the Earth's outer core.

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BibTeXRIS

Felix Gerick, Dominique Jault, Jerome Noir. 2021-01-05. Fast Quasi-Geostrophic Magneto-Coriolis Modes in the Earth's core. https://doi.org/10.1029/2020gl090803

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