COMPOUND ROTATION OF SPIRAL WAVES IN ACTIVE MEDIA WITH PERIODICALLY MODULATED EXCITABILITY

The dynamics of spiral waves under external modulation of excitability is studied experimentally in a light-sensitive convection-free Belous ov-Zhabotinsky medium. When varying the intensity of applied illuminat ion periodically, the experiments reveal strong dependence of the resu lting trajectories of the spiral's tip on the modulation period. With appropriate periodic modulation it is possible to force a meandering s piral wave into the regime of circular (rigid) rotation. The experimen tal results are discussed in the framework of the kinematical theory o f spiral waves.