Chemical Wave Propagation Preserved on an Inhibitory Field in the Ruthenium-Catalyzed Belousov–Zhabotinsky Reaction

The propagation of a chemical wave on an inhibitory field, which was wedged between two excitable fields, was investigated for the photosensitive Belousov–Zhabotinsky (BZ) reaction. With an increase in the width of the inhibitory field between the excitable fields (<i>W</i>), the chemical wave divided into two waves at <i>W</i> = <i>W</i>_α. The divided chemical waves then coalesced at <i>W</i> = <i>W</i>_β with a decrease in <i>W</i>. <i>W</i>_α was larger than <i>W</i>_β, i.e., hysteresis on the width of the inhibitory field was observed between the division and coalescence of the chemical wave. The experimental results were qualitatively reproduced by a numerical calculation based on a three-variable Oregonator model modified for the photosensitive BZ reaction. These results suggest that the chemical wave may be preserved on the inhibitory field due to an activator supplied from a chemical wave on the excitable field