Dresden 2006 – wissenschaftliches Programm

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SYSS: Structure Formation and Self-Organization in non-equilibrium Systems

SYSS 4: Structure Formation and Self-Organization in non-equilibrium Systems III

SYSS 4.3: Hauptvortrag

Freitag, 31. März 2006, 11:15–11:45, HSZ 04

Spatio-temporal chaos and defects in pattern-forming systems — •H. Riecke — Department of Engineering Sciences and Applied Mathematics, Evanston

Many systems undergo bifurcations from a spatially homogeneous state to a state that exhibits spatio-temporal structures. In simple cases the resulting patterns are ordered in space and time. Often, however, they are spatio-temporally chaotic. What is the origin of such states, what mechanisms maintain them, how can they be characterized? For patterns that are stripe-like (lamellar) these questions have been addressed in quite some detail for various systems. In more detail I will present results for spatio-temporal chaos arising from patterns with hexagonal planform. They arise, for instance, in non-Boussinesq fluid convection. I will focus on three states: defect chaos of whirling hexagons, penta-hepta defect chaos in which penta-hepta defects induce the nucleation of dislocations, and whirling chaos driven by the interplay of defects and an oscillatory whirling mode. Our results are based on Ginzburg-Landau, Swift-Hohenberg, and Navier-Stokes equations.