Inducing and modulating spiral waves by delayed feedback in a uniform oscillatory reaction-diffusion system

Spiral waves are induced by delayed feedback in a reaction-diffusion system spontaneously exhibiting a uniform bulk oscillation. Feedback can modulate the spiral wavelength and tip trajectory. For a relatively large feedback intensity (g > 0.45), the spiral wavelength increases monotonously with an increase in delay time. However, when g < 0.45, the wavelength depends non-monotonously on delay time. Spiral waves are rigid for a moderate delay time, and their tip trajectory radius increases with increasing delay time. When delay time exceeds some critical values, spiral waves begin to meander. The traveling wave dispersion relation of the delayed system is computed to account for the spiral wavelength variation with delay time. (C) 2010 Elsevier B.V. All rights reserved.