Stochastic Resonance in Geomagnetic Polarity Reversals

Among noise-induced cooperative phenomena a peculiar relevance is played by stochastic resonance. In this paper we offer evidence that geomagnetic polarity reversals may be due to a stochastic resonance process. In detail, analyzing the distribution function P(τ) of polarity residence times (chrons), we found the evidence of a stochastic synchronization process, i.e., a series of peaks in the P(τ) at T_n≃(2n+1)T_Ω/2 with n=0,1,...,j and T_Ω∼0.1   Myr. This result is discussed in connection with both the typical time scale of Earth’s orbit eccentricity variation and the recent results on the typical time scale of climatic long-term variation.