Slowly rotating, late-type stars show intermittent cyclic magnetic activity, interrupted by grand minima. The record of the solar cycle is apparently chaotic. We construct a simple third-order model of a stellar dynamo following two different procedures. The first uses simple physical arguments based on the processes that occur in a dynamo. The second relies on bifurcation theory, with no explicit reference to the dynamo equations, and displays the essential mathematical structure of the model. Modulation of the basic cycle and chaos are found to be a natural consequence of the transition from a non-magnetic state to one with periodically reversing fields. The model is related to more general normal forms and it is shown that the behaviour described is generic and therefore robust.
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Tobias et al. (1995) studied this question.