Compound rotation of spiral waves in active media with periodically modulated excitability

Abstract The dynamics of spiral waves under external modulation of excitability is studied experimentally in a light-sensitive convection-free Belousov—Zhabotinsky medium. When varying the intensity of applied illumination periodically, the experiments reveal strong dependence of the resulting trajectories of the spiral's tip on the modulation period. With appropriate periodic modulation it is possible to force a meandering spiral wave into the regime of circular (rigid) rotation. The experimental results are discussed in the framework of the kinematical theory of spiral waves.