Statistics of Topological Defects and Spatiotemporal Chaos in a Reaction-Diffusion System

Abstract

The transition between rotating spirals and spatiotemporal chaos (``spiral turbulence'') in an excitable reaction-diffusion system is investigated by means of statistics of topological defects of the concentration 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 change of the defect dynamics within the turbulent regime reveals a strong similarity to a liquid-to-gas transition, while a liquid-solid-like transition occurs upon a jumplike return to the region of spiral stability.