Reversals made simple

It was shown recently that a simple mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha can show a number of features of Earth's magnetic field reversals. This model relies basically on the existence of an exceptional point of the spectrum of the non-selfadjoint dynamo operator. It is shown that highly supercritical dynamos undergo a self-tuning process into a reversal prone state. As a consequence, reversing dynamos might be much more typical and may occur much more frequently in nature than what could be expected from a purely kinematic perspective.