Curvature and propagation velocity of chemical waves

The collision of circular chemical waves in an excitable medium, the Belousov-Zhabotinskii reaction, leads to characteristic cusplike structures. The high curvatures of these structures are especially suitable for experimentally verifying the predicted proportionality between the velocity and the shape of traveling waves. A computerized spectrophotometric video technique with microscopic resolution was used to determine the proportionality factor (2 x 10(-5) square centimeter per second), which in this case is the diffusion coefficient of the autocatalytic species of the reaction system. A numerical calculation of the spatiotemporal evolution of the cusp structure is in good agreement with the experimental observations.