Issue
EPL
Volume 78, Number 4, May 2007
Article Number 44003
Number of page(s) 5
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
DOI http://dx.doi.org/10.1209/0295-5075/78/44003
Published online 07 May 2007
EPL, 78 (2007) 44003
DOI: 10.1209/0295-5075/78/44003

Measuring the anomalous dispersion branch of surface waves on ferrofluids

J. P. Embs1, 2, C. Wagner3, K. Knorr4 and M. Lücke5

1  Institut für Physikalische Chemie, Universität des Saarlandes - Postfach 15 11 50, D-66041, Saarbrücken, Germany
2  Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institut - CH - 5232 Villigen-PSI, Switzerland
3  Institut für Experimentalphysik, Universität des Saarlandes - Postfach 15 11 50, D-66041, Saarbrücken, Germany
4  Fachrichtung Technische Physik, Universität des Saarlandes - Postfach 15 11 50, D-66041, Saarbrücken, Germany
5  Institut für Theoretische Physik, Universität des Saarlandes - Postfach 15 11 50, D-66041, Saarbrücken, Germany


received 19 December 2006; accepted in final form 3 April 2007; published May 2007
published online 7 May 2007

Abstract
In this paper we report on the first experimental investigation of the anomalous dispersion branch of surface waves on ferrofluids in a magnetic field. The existence of such an anomalous dispersion branch has been predicted by several authors, but there has been no experimental evidence for its existence. In our experiments we used the well-known Faraday instability of parametrically excited surface waves on a ferrofluid in the presence of a magnetic field oriented perpendicular to the fluid's surface.

PACS
47.50.Gj - Instabilities.
75.50.Mm - Magnetic liquids.
47.57.-s - Complex fluids and colloidal systems.

© Europhysics Letters Association 2007