Stochastic disk dynamo as a model of reversals of the earth's magnetic field

A stochastic model is given of a system composed ofN similar disk dynamos interacting with one another. The time evolution of the system is governed by a master equation of the class introduced by van Kampen as relevant to stochastic macrosystems. In the model, reversals of the earth's magnetic field are regarded as large deviations caused by a small random force ofO(N ^–1/2) from one of the field polarities to the other. Reversal processes are studied by simulation, which shows that the model explains well the activities of the palaeomagnetic field inclusive of statistical laws of the reversal sequence and the intensity distribution. Comparisons are made between the model and dynamical disk dynamo models.