  The asymmetric time dependence and various statistical properties of polarity
reversals of the Earth's magnetic field are utilized to infer some of the most
essential parameters of the geodynamo, among them the effective (turbulent)
magnetic diffusivity, the degree of supercriticality, and the relative strength
of the periodic forcing which is believed to result from the Milankovic cycle
of the Earth's orbit eccentricity. A time-stepped spherically symmetric
alpha^2-dynamo model is used as the kernel of an inverse problem solver in form
of a downhill simplex method which converges to solutions that yield a stunning
correspondence with paleomagnetic data.
