Dynamo action in a rotating convective layer

摘要: We study dynamo processes in a convective layer of Boussinesq fluid rotating about the vertical. Irrespective rotation, if magnetic Reynolds number is large enough, convection acts as an efficient small-scale with growth time comparable turnover and capable generating substantial amount energy. When rotation important (large Taylor number) characteristic horizontal scale decreases flow develops well-defined distribution kinetic helicity antisymmetric mid-plane. find no convincing evidence large-scale action associated this distribution. Even when strong, energy at scales remains small, that non-rotating case. By externally imposing uniform field, we measure average electromotive force. quantity to be extremely strongly fluctuating, are able compute $\alpha$ -effect only after very long averaging. In those cases for which reasonable convergence achieved, controlled by diffusivity. Thus demonstrate existence system whose rate turbulent, i.e. independent diffusivity, but laminar, dependent on The implications these results problem generation strong mean fields discussed.