Effects of fluctuation on alpha-omega dynamo models

We analyse the role of a fluctuating alpha-effect in alpha-omega dynamo models, and show that there is a mechanism for magnetic field generation, valid at large scale separation, deriving from the interaction of mean shear and a fluctuating alpha-effect. It is shown that this effect can act as a dynamo even in the absence of a mean alpha-effect, and that the timescale for dynamo waves is strongly affected by the presence of fluctuations.