Meandering spiral waves in a bubble-free Belousov–Zhabotinsky reaction with pyrogallol

A thin layer of the Belousov–Zhabotinsky reaction with pyrogallol (PG) supports meandering spiral waves with outward-petal trajectories. Increasing [PG] or lowering [H2SO4] leads to an enlargement of the outer diameter of the tip trajectory, as well as an increment of the number of petals. Far from the spiral tip, the wavelength and the wave period also increase. However, the wave speed decreases, when [PG] is elevated or [H2SO4] is reduced. This reaction is suitable for further investigations of three-dimensional spiral dynamics with optical tomography because of slowly propagating waves, no bubbles, no induction time, and no inhibitory effects of oxygen.