Angular frequency of rotating spiral waves in a chemical reaction-diffusion system

Rotating spiral waves have been observed in various excitable physical, chemical, and biological reaction-diffusion systems. Most of the theoretical and experimental studies of two-dimensional excitable systems were done in planar geometries. However, in nature, many excitation waves occur on curved surfaces, e.g., the heart, the visual cortex, or the retina. In the framework of kinematic approach it has been shown, that the spiral wave's angular frequency depends on the curvature of the system itself. The chemical Belousov-Zhabotinsky reaction can be used as a model system to investigate the propagation dynamics of these spirals. We use quasi-two-dimensional hemispherical shells with various curvatures to determine experimentally the curvature dependence of the spiral's rotational frequency.