Wave initiation through spatiotemporally controllable perturbations.

(Received 13 November 2002; published 9 April 2003)We study the initiation of pulses and fronts in a two-dimensional catalytic reaction-diffusion system:CO oxidation on Pt(110). Using a computer-controlled mobile focused laser beam, we impart variouspatterns (in space and time) of localized temperature ‘‘kicks’’ to the surface. We explore, and alsorationalize through modeling, the cooperativity of such individually subcritical perturbations in boththe excitable and the bistable regime.