Common mechanism links spiral wave meandering and wave-front-obstacle separation

Spiral waves rotate either around a circular core or meander, inscribing a noncircular pattern. The medium properties determining the transition of meandering were found to be equivalent to those defining the transition from wave tip separation and attachment around the end of an unexcitable strip of thickness comparable to zero velocity wave-front thickness. The transition from circular to noncircular tip movement is analytically predicted by the balance of the diffusive fluxes within the boundary layer at the wave tip.