Spiral-wave dynamics in a simple model of excitable media: The transition from simple to compound rotation

Two-dimensional reaction-diffusion equations with simple reaction kinetics are used to study the dynamics of spiral waves in excitable media. Detailed numerical results are presented for the transition from simple (periodic) rotation to compound (quasiperiodic) rotation of spiral waves. It is shown that this transition occurs via a supercritical Hopf bifurcation and that there is no frequency locking within the quasiperiodic regime.