Interaction between dynamos at different scales

We study the interaction between dynamos with different spatial and temporal scales. In particular, we consider cases in which the smaller of the dynamo systems is itself unstable to dynamo action. We find that the degree of interaction depends on the magnetic Reynolds number, and the relative amplitude between the driving velocities at different scales. Even though it is possible to construct cases in which one or other of the two scales has negligible effect on the overall dynamo action, in general the composite system displays a significant interaction between scales.