Electronic edition ISSN 1574-0579

Cosmic magnetic fields in theory and experiment: The role of harmonic forcings

F. Stefani¹ , G. M. Horstmann¹ , G. Mamatsashvili^1,2 , T. Weier¹

¹ Helmholtz-Zentrum Dresden -- Rossendorf, Bautzner Landstr. 400, 01328 Dresden, Germany
² Abastumani Astrophysical Observatory, Abastumani 0301, Georgia

Abstract
Recent decades have seen great progress in the experimental investigation of fundamental processes that are relevant to geophysical and astrophysical magnetohydrodynamics. After summarizing the results of the most important liquid-metalexperiments on the dynamo effect, the magnetorotational instability and Alfvén waves, we sketch some new results concerning helicity oscillations in convection and their synchronization by time-dependent tide-like forces. Closely related to these experimental efforts, we discuss the potential role of harmonic forcings in synchronizing the solar dynamo or triggering reversals of the geodynamo. A special focus lies then on the DRESDYN precession-driven dynamo experiment which is presently in the commissioning phase. Figs 2, Refs 18.