Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
Reversals made simple: some new results
Stefani, F.; Gerbeth, G.; Günther, U.; Xu, M.; Sorriso-Valvo, L.
We present new results of a very simple model of Earth's magnetic field reversals which is based on an alpha^2 dynamo under the influence of noise. This reversal model relies on the existence of exceptional points of the spectrum of the non-selfadjoint dynamo operator. As new aspects of this model, we delineate its connection with the van der Pol oscillator, we demonstrate a remarkable agreement with the characteristic time scales and the well-known asymmetry of real reversals, and we discuss the deviation from Poissonian statistics in real reversal sequences and in our model. Finally, we present some speculations on the influence of the size of the inner core on the spectral properties of the dynamo operator and on the reversal rate.
9th MHD Days 2006, 04.-05.12.2006, Heidelberg, Germany