TRANSITION FROM SIMPLE ROTATING CHEMICAL SPIRALS TO MEANDERING AND TRAVELING SPIRALS

Experiments on the Belousov-Zhabotinksy reaction unfold the bifurcatio n from simple (temporally periodic) rotating spirals to meandering (qu asiperiodic) spirals in the neighborhood of a codimension-2 point. The re are two types of meandering spirals, inward-petal (epicycloid) spir als and outward-petal (hypocycloid) spirals. These two types of meande ring regimes are separated in the phase diagram by a line of traveling spirals that terminates at the codimension-2 point. The observations are in good accord with theory.