1 research outputs found
Via Hexagons to Squares in Ferrofluids: Experiments on Hysteretic Surface Transformations under Variation of the Normal Magnetic Field
We report on different surface patterns on magnetic liquids following the
Rosensweig instability. We compare the bifurcation from the flat surface to a
hexagonal array of spikes with the transition to squares at higher fields. From
a radioscopic mapping of the surface topography we extract amplitudes and
wavelengths. For the hexagon--square transition, which is complex because of
coexisting domains, we tailor a set of order parameters like peak--to--peak
distance, circularity, angular correlation function and pattern specific
amplitudes from Fourier space. These measures enable us to quantify the smooth
hysteretic transition. Voronoi diagrams indicate a pinning of the domains. Thus
the smoothness of the transition is roughness on a small scale.Comment: 17 pages, 14 figure