Coexisting stochastic and coherence resonance in a mean-field dynamo model for Earth's magnetic field reversals
Forschungszentrum Dresden-Rossendorf, PO Box 510119, 01314 Dresden, Germany
Corresponding author: a F.Stefani@fzd.de
Revised: 7 July 2008
Published online: 19 September 2008
Using a spherically symmetric mean-field α2-dynamo model for Earth's magnetic field reversals, we show the coexistence of the noise-induced phenomena coherence resonance and stochastic resonance. Stochastic resonance was recently invoked to explain the 100 kyr periodicity in the distribution of residence times between reversals. The comparison of the resulting residence time distribution with the paleomagnetic one allows for some estimate of the effective diffusion time of the Earth's core which may be 100 kyr or slightly below rather than 200 kyr as it would result from the molecular resistivity.
PACS: 91.25.Mf – Magnetic field reversals: process and timescale / 91.25.Cw – Origins and models of the magnetic field; dynamo theories / 05.40.Ca – Noise
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008