title: Retarding the growth of the Rosensweig instability unveils a new scaling regime.
abstract: Using a highly viscous magnetic fluid, the dynamics in the aftermath of the Rosensweig instability can be slowed down by more than 2000 times. In this way we expand the regime where the growth rate is predicted to scale linearly with the bifurcation parameter by six orders of magnitude, while this regime is tiny for standard ferrofluids and cannot be resolved experimentally there. We measure the growth of the pattern by means of a two-dimensional imaging technique, and find that the slopes of the growth and decay rates are not the same-a qualitative discrepancy with respect to the theoretical predictions. We solve this discrepancy by taking into account a viscosity which is assumed to be different for the growth and decay. This may be a consequence of the measured shear thinning of the ferrofluid.
authors.affiliation: TU Dresden, Institute of Fluid Mechanics, D-01062 Dresden, Germany.
authors.forename: Adrian
authors.initials: A
authors.lastname: Lange
authors.affiliation: Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Gollwitzer
authors.affiliation: Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Robin
authors.initials: R
authors.lastname: Maretzki
authors.affiliation: Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Rehberg
authors.affiliation: Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Richter