Core Expansion and Spiral Breakup in Oscillatory Recovering Media

We studied a new type of meandering of spiral waves in oscillatory recovering media using the modified Barkley’s model. The core region expands, and the spiral tip follows itself an outward spiral-like trajectory. The spiral waves then break up near the center of rotation, leading to spatiotemporal irregularity. This mechanism, as pointed out by Garfinkel, is still unknown. We investigate the effect of the local dynamics and fixed points and study the transition to meandering and core expansion as the control parameter is varied. The resulting non-monotonic dispersion curve has implications about similar behavior observed in the restitution curve and attributed to double-wave reentry by other authors.