Waves in the Earth’s Core

Project Funder: NERC

Project lead and collaborators: Chris Jones and Steve Tobias

 Research Theme: Geophysical Flows

Summary of project

The Earth’s magnetic field is now continuously monitored from space by a swarm of satellites, and more data has been gathered from magnetic observatories in the past. Since the Earth’s magnetic field is generated in the fluid outer core of the Earth, by looking for the wave components in the magnetic data we can potentially discover information about the nature of the inside of the Earth. Data from observing waves in the Sun, helioseismology, has completely transformed our knowledge about the solar interior, and in this project we hope to do a similar job for the deep interior of the Earth. However, the waves we are looking for are very strongly affected by the rapid rotation of the Earth and its magnetic field. We first need to understand how these waves work, how to see them in the geomagnetic signal, and how their frequencies and wavelengths relate to the physical conditions in the Earth’s core. The project is therefore focussed on understanding waves in a rapidly rotating spherical shell in the presence of magnetic field.

The first image is a wave train visible in the Earth’s magnetic field at the Earth’s Core-Mantle boundary in the year 2000, courtesy of Prof. Andrew Jackson (2003). The second image is from Hori, Jones and Teed (2015), and show waves in a numerical simulation of the Earth’s core.  Φ is the longitude angle and t is the time. Magnetic features move to lower Φ (westward) as time increases.

 Relevant links

Hori, K., Jones, C.A. and Teed, R.J. (2015). All recent papers can be found at http://www.maths.leeds.ac.uk/index.php?id=263&uid=1033