title: Growth of surface undulations at the Rosensweig instability.
abstract: We investigate the growth of a pattern of liquid crests emerging in a layer of magnetic liquid when subjected to a magnetic field oriented normally to the fluid surface. After a steplike increase of the magnetic field, the temporal evolution of the pattern amplitude is measured by means of a Hall-sensor array. The extracted growth rate is compared with predictions from linear stability analysis by taking into account the proper nonlinear magnetization curve M(H) . The remaining discrepancy can be resolved by numerical calculations via the finite-element method. By starting with a finite surface perturbation, it can reproduce the temporal evolution of the pattern amplitude and the growth rate. The investigations are performed for two magnetic liquids, one with low and one with high viscosity.
authors.affiliation: Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Knieling
authors.forename: Reinhard
authors.initials: R
authors.lastname: Richter
authors.forename: Ingo
authors.initials: I
authors.lastname: Rehberg
authors.forename: Gunar
authors.initials: G
authors.lastname: Matthies
authors.forename: Adrian
authors.initials: A
authors.lastname: Lange