On the α‐effect for slow and fast rotation

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Abstract
This paper deals with the influence of global rotation on a special inomogeneous field of incompressible turbulence. All its deviations from homogeneity and isotropy may be described only by a constant gradient of turbulence intensity. Using a FOURIER representation we are able to determine the α‐effect for any given rotational rates and material constants. In the case of slow rotation our expressions show a strong similarity with those of other authors. Increasing angular velocities do not – as is to be assumed at first sight – suppress the production of mean electromotive force caused by turbulence. They rather lead to a two‐dimensionality of this e.m.f. with respect to the axis of rotation. It seems, therefore, that very fast rotation can not completely delete the dynamo instability.