The DRESDYN project: Liquid metal experiments on dynamo action and magnetorotational instability

The dynamo effect in moving electrically conducting fluids is at the root of magnetic field generation in planets and stars. Yet, cosmic magnetic fields play also an active role in the formation of central objects, such as protostars and black holes, by destabilizing accretion disks that would be hydrodynamically stable. While often studied separately, dynamo action and magnetically triggered instabilities may also occur together in such highly non-linear processes as the MRI dynamo or the Tayler-Spruit dynamo.

The DRESDYN project at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) serves as a platform for continuing the liquid metal experiments of the last two decades which were related to dynamo action and magnetically triggered flow instabilities. After a short survey of the dynamo experiments in Riga, Karlsruhe and Cadarache, and the various MRI experiments at the PROMISE facility at HZDR, I discuss the preparatory status of a large-scale precession experiment and a Taylor-Couette experiment for investigating various forms of the MRI and their combinations with the Tayler instability. Special focus will be laid on the numerical predictions of both experiments, as well as on some recent findings concerning the relation of non-modal growth in rotating flows with dissipation-induced instabilities, such as helical and azimuthal MRI for negative and positive shear.