Fast Quasi-Geostrophic Magneto-Coriolis Modes in the Earth's core
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.
Keywords
Cite
@article{arxiv.2101.01493,
title = {Fast Quasi-Geostrophic Magneto-Coriolis Modes in the Earth's core},
author = {Felix Gerick and Dominique Jault and Jerome Noir},
journal= {arXiv preprint arXiv:2101.01493},
year = {2021}
}