Laboratory experiments and numerical simulations on magnetic instabilities

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With the successful dynamo experiments in Riga, Karlsruhe and Cadarache a worldwide community has been established whose activities are devoted to the investigation of dynamo action in liquid metal flows. Presently, the focus of liquid metal experiments is shifting towards a better understanding of magnetic instabilities and wave phenomena in rotating flows. Most prominent among them is the magnetorotational instability (MRI) which is not only essential in destabilizing accretion disk around black holes and protostars, but which might also play an important role in the angular momentum transport in planetary dynamos. Evidence for the appearance of MRI was obtained recently with the cylindrical Taylor-Couette experiment PROMISE (Potsdam ROssendorf Magnetic InStability Experiment) under the influence of a helical magnetic field. The project is intended to exploit and strengthen the existing experimental basis for further investigations of related but nonaxisymmetric magnetic instabilities: the azimuthal MRI, the first instabilities in a magnetized spherical Couette flow, and the Tayler instability. The experiments will be supported by accompanying numerical work, with particular focus on simulations of small magnetic Prandtl number flows.