Synchrony and the emergence of chaos in oscillations on supported catalysts

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Abstract
Complex behavior of an oscillating reaction on an array of catalytic regions was modeled using a distributed model consisting of a 10×10 matrix with ten randomly placed oscillators coupled via heat transfer. Each single oscillator was described by a very simple system of two differential equations chosen to model the CO/NO reaction on supported Pd. However, the coupled system exhibited very complex behavior with periodic oscillations, period multiplications, beat structures and chaos. All of these complex features predicted by the model have also been found in experiments. In addition, the model was able to predict the experimentally observed tendencies in the development of complex behavior with changing reaction conditions. Changing distributions of the cells or introducing small differences in the description of the single oscillators did not change the principal features of the system. However, the transition to chaos could be changed in that for one distribution of active cells a Feigenbaum sequence to chaos was found but not in another. With one oscillator twice as active as the rest of the cells, the high activity cell was dominant and entrained the whole system, leading to completely synchronized behavior. Also in this situation, however, chaotic responses were found, when the high activity oscillator was in a stable ignited state. Possible generalizations of this treatment to other oscillating systems are discussed.