Shock structures and bunching fronts in excitable reaction-diffusion systems.
We report experimental results on the dynamics of excitation waves in a modified Belousov-Zhabotinsky reaction. The waves in this system obey nonmonotonic dispersion relations. This anomaly induces the stacking of excitation fronts into patterns with stable interpulse distances. The stacking process creates either a traveling shock structure or a cascade of bunching events in which metastable wave packets are formed. The direction and the speed of the shock are explained in terms of a simple geometrical analysis. We also present experimental evidence for the corresponding instabilities in two-dimensional systems. Here, wave stacking generates atypical structures in the collision of target patterns and wave bunching is accompanied by complex front deformations.
Hamik
Chad T
CT
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
Steinbock
Oliver
O
D003512:Cyclohexanones / Q000737:chemistry; D004594:Electrophysiology; D008954:Models, Biological; D009991:Oscillometry / Q000379:methods; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry; D015398:Signal Transduction
D003512:Cyclohexanones; D010618:Phenanthrolines; C001635:ferroin