WAVE COMPETITION IN EXCITABLE MODULATED MEDIA

The propagation of an initially planar front is studied within the fra mework of the photosensitive Belousov-Zhabotinsky reaction modulated b y a smooth spatial variation of the local front velocity in the direct ion perpendicular to front propagation. Under this modulation, the wav e front develops several fingers corresponding to the local maxima of the modulation function. After a transient, the wave front achieves a stationary shape that does not necessarily coincide with the one exter nally imposed by the modulation. Theoretical predictions for the selec tion criteria of fingers and steady-state velocity are experimentally validated.