MEANDERING INSTABILITY OF A SPIRAL INTERFACE IN THE FREE-BOUNDARY LIMIT

The two-component reaction-diffusion excitable medium is treated numer ically in the free boundary limit for the fast field. We find that the spiral interface is stable for a sufficiently high diffusion constant of the slow held. The spiral wave (interface) undergoes a core-meande r instability via a forward Hopf bifurcation as the diffusion constant decreases. A further decrease of the diffusion constant is found to r esult in the onset of hypermeandering and spiral breakup. We demonstra te quantitative convergence of the dynamics of reaction-diffusion syst em to its free boundary limit.