Abstract
In an attempt to understand why the dominating magnetic field observed in the von-Kármán-sodium (VKS) dynamo experiment is axisymmetric, we investigate in the present article the ability of mean field models to generate axisymmetric eigenmodes in cylindrical geometries. An α-effect is added to the induction equation and we identify reasonable and necessary properties of the α distribution so that axisymmetric eigenmodes are generated. The parametric study is done with two different simulation codes. We find that simple distributions of α-effect, either concentrated in the disk neighborhood or occupying the bulk of the flow, require unrealistically large values of the parameter α to explain the VKS observations.
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