Oscillatory clusters in a photosensitive Belousov-Zhabotinsky reaction
system with global feedback
The Belousov-Zhabotinsky (BZ) reaction has been
widely used as a prototype system for the study of chemical oscillations
and pattern formation for over 30 years. The BZ reaction-diffusion system
has been utilized primarily to understand the dynamics of patterns consisting
of traveling waves, including target patterns and spiral waves. However,
the non-traveling types of patterns found in other chemical oscillating systems
have not been observed in the autonomous, homogeneous BZ reaction.
Examples of non-traveling patterns include Turing
structures and standing oscillatory patterns: waves and clusters. Clusters
consist of sets of domains in which nearly all of the elements in a domain
oscillate with the same amplitude and phase. They resemble standing waves,
but possess no intrinsic wavelength.
The photosensitive Ru(bpy)3-catalyzed BZ reaction
provides an effective way to control oscillations by light illumination.
By applying global feedback, we successfully obtained families of cluster
patterns: two-phase clusters display antiphase oscillations; three-phase
clusters contain three sets of domains with a phase shift equal to one third
of the period of the local oscillation; irregular cluster with spatiotemporal
chaos; localized irregular and regular clusters.
Oscillatory clusters play an important role in understanding coupled neural systems,
information storage and retrieval in distributed memory.
Our results were published in
NATURE, 406, 389 (2000),
and
Phys. Rev. E 62, 6414 (2000).
Click here for the realistic BZ model
Spiral stop rotation to oscillatory cluster (AVI movie file:14MG)
