Slow magnetic Rossby waves in the Earth's core

Hori, K., Jones, C.A. and Teed, R.J. (2015) Slow magnetic Rossby waves in the Earth's core. Geophysical Research Letters, 42(16), pp. 6622-6629. (doi: 10.1002/2015GL064733)

Abstract

The westward drift component of the secular variation is likely to be a signal of waves ridingon a background mean flow. By separating the wave and mean flow contributions, we can infer the strengthof the “hidden” azimuthal part of the magnetic field within the core. We explore the origin of the westwarddrift commonly seen in dynamo simulations and show that it propagates at the speed of the slow magneticRossby waves with respect to a mean zonal flow. Our results indicate that such waves could be excited inthe Earth’s core and that wave propagation may indeed play some role in the longitudinal drift, particularlyat higher latitudes where the wave component is relatively strong, the equatorial westward drift beingdominated by the mean flow. We discuss a potential inference of the RMS toroidal field strength within theEarth’s core from the observed drift rate.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Teed, Dr Robert
• Authors: Hori, K., Jones, C.A., and Teed, R.J.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Geophysical Research Letters
• Publisher: Wiley
• ISSN: 0094-8276
• ISSN (Online): 1944-8007
• Published Online: 20 August 2015
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Geophysical Research Letters 42(16):6622-6629
• Publisher Policy: Reproduced under a Creative Commons License