Reversals of the Geomagnetic Field: A Multi-Scale Phenomenon?

It is shown that during geomagnetic field reversals in three-dimensional dynamo models, synchronization of the magnetic field on different scales can occur. For even modes relative to the equatorial plane, synchronization is reduced to a simultaneous decrease in the amplitude of the modes. For odd numbers it is a synchronous change of polarity. As a result, magnetic field reversals occur on several spatial scales simultaneously.