Reversal of spiral waves in an oscillatory system caused by an inhomogeneity.

Spatial heterogeneities are commonly found in realistic systems and play significant roles in dynamics of spiral waves. We here demonstrate a novel phenomenon that a localized inhomogeneity put around the spiral core could lead to the reversal of spiral waves in an oscillatory system, e.g., the complex Ginzburg-Landau equation. With the amplitude-phase representation, we analyze underling mechanism and conditions of the wave reversal in detail, which is found to agree with the numerical evidence.