Dresden 2009 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 20: Focused Session: Pattern formation in colloidal and granular systems

DY 20.1: Hauptvortrag

Donnerstag, 26. März 2009, 09:30–10:00, HÜL 386

Magnetic granular matter: from lattices to self-assembled swimmers — •Igor Aranson, Alexey Snezhko, Maxim Belkin, and Wai Kwok — Materials Science Division, Argonne National Laboratory, Argonne, IL60439

Fundamental mechanisms governing pattern formation and self-assembly in granular matter with complex interactions have been attracting enormous attention in the physics community. I will discuss novel dynamic patterns formed at magnetically driven granular matter: self-assembled magnetic surface swimmers: magnetic snakes. The snakes self-assemble from a dispersion of magnetic microparticles suspended on the liquid-air interface and subjected to an alternating magnetic field. The self-propulsion mechanism is related to a spontaneous symmetry breaking instability of the self-generated surface flows. We present a phenomenological model which reproduces observed features of the magnetic surface swimmers. In addition, formation of snakes is captured by hybrid molecular dynamics simulations of magnetic particles on the surface of fluid.