Oscillatory clusters in a reaction–diffusion system switching between excitable and unexcitable states

In this study, we report the observation of oscillatory clusters in the photosensitive Belousov–Zhabotinsky reaction switching between excitable and unexcitable states. Numerical studies with a three-variable Oregonator model have been carried out in oneand two-dimensional media. Both non-flux and periodic boundaries have been characterized. Twoand three-phase clusters with standing, breathing, and irregular segregations are achieved when the intensity and durations of the two phases of the square-wave forcing are varied. The occurrence of oscillatory clusters in the excitable medium is due to the dual functions of the inhibitory light perturbation, i.e. eliminating existing wave activity as observed in earlier studies and initiating pattern formation at unexcited regions. The unusual positive impact of the inhibitory perturbation is analyzed, based on the flow trajectories of the system in a two-dimensional concentration phase plane.