M. Hildebrand et al., STATISTICS OF TOPOLOGICAL DEFECTS AND SPATIOTEMPORAL CHAOS IN A REACTION-DIFFUSION SYSTEM, Physical review letters, 75(8), 1995, pp. 1503-1506
The transition between rotating spirals and spatiotemporal chaos (''sp
iral turbulence'') in an excitable reaction-diffusion system is invest
igated by means of statistics of topological defects of the concentrat
ion field. The ratio of the variance and the mean value of the number
of defects show a significant deviation from unity at this point. A ch
ange of the defect dynamics within the turbulent regime reveals a stro
ng similarity to a liquid-to-gas transition, while a liquid-solid-like
transition occurs upon a jumplike return to the region of spiral stab
ility.