I. Aranson et al., BOUNDARY-INDUCED DRIFT OF SPIRALS IN EXCITABLE MEDIA, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 50(4), 1994, pp. 180002395-180002398
The motion of a spiral wave in an excitable medium due to interaction
with a boundary is considered. The drift of the core and the frequency
shift, evaluated analytically as a response to a small perturbation o
f the boundary, are found to be superexponentially weak. It is shown t
hat for some range of parameters the spiral is unstable to small displ
acements away from the center of a circular domain.