Pattern formation in a surface chemical reaction with global delayed feedback.
We consider effects of global delayed feedback on anharmonic oscillations in the reaction-diffusion model of the CO oxidation reaction on a Pt(110) single-crystal surface. Depending on the feedback intensity and the delay time, we find that various spatiotemporal patterns can be induced. These patterns are characterized using a transformation to phase and amplitude variables designed for anharmonic oscillations. Typical feedback-induced patterns represent traveling phase flips, asynchronous oscillations, and dynamical clustering. Three different types of cluster patterns are identified: amplitude clusters, phase clusters, and cluster turbulence. For phase clusters, two different front instabilities are possible. A pitchfork bifurcation leads to propagation of cluster fronts. An instability of the state of phase balance results in spatial front oscillations.
Bertram
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Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
Mikhailov
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