Complex Structures in Rotating Systems

Hermann Riecke

Northwestern University

Convection has served as an excellent system for the study of pattern formation. By applying rotation to the system it becomes non-variational even right at onset allowing for complex dynamics. I will briefly review some aspects of the impact of rotation on roll-type convection patterns focussing on the Kueppers-Lortz instability. Then I will discuss our recent results on the effect of rotation on hexagonal planforms. For steady weakly nonlinear hexagons we find spatio-temporal chaos triggered by induced nucleation. We show that oscillating hexagons are typically described by the two-dimensional complex Ginzburg-Landau equation in a regime of defect chaos. Using the Navier-Stokes equations we find whirling chaos and study the statistics of defects in the pattern.