Superlattice Turing Patterns: Why Not?

Thursday, May 14, 1998 - 11:00am - 12:00pm
Keller 3-180
Mary Silber (Northwestern University)
Superlattice patterns are characterized as having spatial structure on two disparate length scales; they are spatially-periodic on the large scale, and have beautiful intricate structure on the smaller scale. Such patterns were recently observed in experiments on parametrically-excited surface waves by Kudrolli, Pier and Gollub. I will review results of equivariant bifurcation theory that show that patterns similar to those seen in the experiments arise in a generic symmetry-breaking bifurcation of a spatially-uniform state. These bifurcation results will then be applied to a general two-component reaction-diffusion system in the vicinity of a Turing instability. By considering a particular degenerate bifurcation problem we are able to show that the transitions observed in the hydrodynamic problem cannot be reproduced in the chemical reaction-diffusion system.