A Heteroclinic Model of Geodynamo Reversals and Excursions
The Earth’s magnetic field is by and large a steady dipole, but its history has been punctuated by intermittent excursions and reversals. This is at least superficially similar to the behaviour of differential equations containing structurally stable heteroclinic cycles. We present a model of the geodynamo that is based on the symmetries of velocity fields in a rotating spherical shell, and that contains such a cycle. Patterns of excursions and reversals that resemble the geomagnetic record can be obtained by introducing small symmetry-breaking terms.
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- 1.Merrill, R.L., McElhinny, M.W. & McFadden, P.L. (1996) The Magnetic Field of the Earth: Paleomagnetism, the Core, and the Deep Mantle. Academic Press: San Diego.Google Scholar
- 3.Busse, F.H. (2001) In this volumeGoogle Scholar
- 4.Roberts, P.H. (2001) In this volumeGoogle Scholar
- 9.Robbins, K.A. (1975) Disk Dynamos and Magnetic Reversal (PhD thesis, M.I.T.)Google Scholar
- 10.Chui, A.Y.K. & Moffatt, H.K. (1993) A thermally driven disc dynamo. In Solar and Planetary Dynamos (ed. M.R.E. Proctor, P.C. Matthews & A.M. Rucklidge), pp. 51–58. Cambridge University Press: CambridgeGoogle Scholar
- 11.Hide, R., Skeldon, A.C. & Acheson, D.J. (1996) A study of two novel self-exciting single-disk homopolar dynamos: theory, Proc. R. Soc. Lond. A 452 1369–1395Google Scholar
- 22.Melbourne, L, Proctor, M.R.E. & Rucklidge, A.M. (2001) In preparationGoogle Scholar