Linear and nonlinear approach to the Rosensweig instability


Abstract

We report on recent efforts to improve the understanding of the Rosensweig instability in the linear as well as in the nonlinear regime. In the linear regime we focus on the wavenumber of maximal growth and the oscillatory decay of metastable magnetic liquid ridges, accessible via a new pulse technique. We compare the measurements with the predictions of the linear stability analysis. In the nonlinear regime the fully developed Rosensweig pattern was successfully estimated by the method of finite elements, taking into account the nonlinear magnetization law. For a comparison with these results the three-dimensional surface profile is recorded by a radioscopic measurement technique. The bifurcation diagram measured in this way can be fitted by the roots of an amplitude equation. Eventually we investigate ferrosolitons, which were recently uncovered in the bistability interval of the Rosensweig instability.


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