Mr Chris Davies

Postgraduate student

Contact details

Telephone extension: 38192

Email address: scs1cd@leeds.ac.uk

Room: B.09, 15-19 Hyde Terrace

Links

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Project details

Project title: Why does the Earth's magnetic field reverse and what causes superchrons?

Supervisors: Professor David Gubbins and Professor Peter Jimack (School of Computing)

Start date: October 2005

This project involves the analysis of geodynamo simulations that produce magnetic fields that are locked to the core-mantle boundary. Locking is of interest due to observations of the historical and paleomagnetic field: four high latitude flux patches tend to retain steady positions throughout the historical record, virtual geomagnetic pole paths appear to favour two longitudinal bands during reversals and secular variation appears to be below average in the Pacific hemisphere. These observations suggest a nonaxisymmetric influence of the mantle, exerted on the core fluid. Locking is achieved by incorporating an inhomogeneous heat flux boundary condition into the problem formulation, derived from seismic tomography.

My work involves the exploration of parameters regimes that permit field locking and the interpretation of these simulations in a paleomagnetic context. Tools have been developed for post-processing and visualisation of simulation data and for comparison with observational data. Fluid mechanical aspects are also considered, including boundary resonance and failure of the dynamo at Rayleigh numbers marginally above criticality. Finally, the work will incorporate a benchmark between the spectral dynamo code developed at the University of Leeds, and a finite element code developed at the University of Exeter.