Complex periodic spirals and line-defect turbulence in a chemical system

Recent numerical simulations on two-dimensional model reaction-diffusion systems have revealed unusual spiral waves with complex oscillations and turbulent patterns, both mediated by “line defects.”Here we report the observation of such patterns in a laboratory experiment for the first time; complex spiral waves with period-2 and period-3 and turbulent patterns filled with a tangle of line defects are observed and their spatiotemporal dynamics are elucidated by line defects. Since line defects are a generic property of complex periodic media, the observed patterns are expected to arise in a broad class of complex periodic systems.