Spiral-core meandering in excitable media

Abstract
The rotating spiral pattern seen in a variety of excitable systems is known to undergo a secondary instability referred to as tip meandering. In the limit of a small (but nonzero) diffusion-constant ratio for a two-component reaction-diffusion model of an excitable medium, we derive the existence of this instability; this requires solving the linear problem defined by expanding about the spiral-core steady-state solution found by Bernoff [Physica D 53, 125 (1991)]. We comment on how these results might lead to a full theory of core meandering.