Detlef Elstner

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We consider the effect of toroidal magnetic fields on hydrodynamically stable Taylor-Couette differential rotation flows. For current-free magnetic fields a nonaxisymmetricm = 1 magnetorotational instability arises when the magnetic Reynolds number exceeds O(100). We then consider how this ‘azimuthal magnetorotational instability’ (AMRI) is modified if the(More)
We investigate the evolution of three-dimensional (3D), large-scale galactic magnetic fields under the influence of time dependent gas flows in spiral arms and excited by a turbulent dynamo. Our principal goal is to check how the enhanced turbulent diffusion in spiral arms affects the global magnetic field structure evolving under the influence of the(More)
The question is answered whether α-shell-dynamos are able to produce a cyclic activity or not. Only kinematic dynamos are considered and only the solutions with the lowest dynamo number are studied without restrictions about the axial symmetry of the solution. The α-effect is allowed to be latitudinally inhomogeneous and/or anisotropic, but it is assumed as(More)
Recent simulations of supernova-driven turbulence within the ISM support the existence of a large-scale dynamo. With a growth time of about two hundred million years, the dynamo is quite fast – in contradiction to many assertions in the literature. We here present details on the scaling of the dynamo effect within the simulations and discuss global(More)
The evolution of a stellar dipolar-type magnetosphere interacting with a Keplerian disk is investigated numerically using the ideal MHD ZEUS-3D code in the axisymmetry option. We compute the innermost region around the stellar object using a non-smoothed gravitational potential. The disk is taken as a boundary condition prescribing the mass inflow into the(More)
The evolution of a stellar dipolar-type magnetosphere interacting with a Keplerian disk is investigated numerically using the ideal MHD ZEUS-3D code in the axisymmetry option. We compute the innermost region around the stellar object using a non-smoothed gravitational potential. The disk is taken as a boundary condition prescribing the mass inflow into the(More)