A Stochastic Description of Fluctuations and Polarity Reversals in the Earth's Magnetic Field

Bruce Buffett, University of California, Berkeley
November 5th, 2014 at 3:30PM–4:30PM in 939 Evans Hall [Map]

The Earth's magnetic field must be continuously regenerated by convection in the liquid metal core to overcome persistent losses due to ohmic decay. Numerical models are capable of producing a self-sustaining magnetic field, but computational limitations prevent solutions with realistic physical properties. Consequently, efforts to apply these models to geological records of the magnetic field are open to question. An alternative approach relies on a stochastic model, which takes advantage of a separate of time scales between short-period convection fluctuations and long-period variations in the dipole field. A stochastic model is constructed from geological observations to provide a simple interpretation of magnetic reversals. Allowing for correlated noise in the stochastic model offers insights into the lifetime of convective eddies in the liquid metal core.