SPINNING FERROFLUID MICROSCOPIC DROPLETS
E.
Janiaud, F. Elias, J.-C. Bacri, V. Cabuil, and R. Perzynski
We investigate experimentally the behavior of microscopic ferrofluid
droplets under the effect of a rotating external magnetic field. Depending on
the system control parameters, the drops adopt fascinating shapes, like
starfish, rod-like or pancake shapes, co-rotating with the external field, but
also creeping snakes, swirling loops, and rings. We describe these structures
and classify them in a phase diagram. With simple arguments, we discuss the
droplet dynamics and morphology in each phase.
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