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Oliver Rudzick and Alexander S. Mikhailov
A new kind of nonlinear nonequilibrium patterns - twisted spiral waves - is predicted for periodically forced oscillatory reaction-diffusion media. We show furthermore that, in such media, spatial regions with modified local properties may act as traps where propagating waves can be stored and released in a controlled way. Underlying both phenomena is the effect of the wavelength-dependent propagation reversal of traveling phase fronts, always possible when homogeneous oscillations are modulationally stable without forcing. The analysis is performed using as a model the complex Ginzburg-Landau equation, applicable for reaction-diffusion systems in the vicinity of a supercritical Hopf bifurcation. As an example for a realistic model describing a reaction-diffusion system we present numerical results obtained with the Krischer-Eiswirth-Ertl model for the catalytic CO oxidation on Pt(110). Using a temperature-dependent variant of the model it is demonstrated that wave propagation reversal is present for subharmonic forcing as well as for superharmonic forcing. Inhomogeneities of the surface temperature can be used to construct wave traps in 1d and 2d. [1] O. Rudzick and A. S. Mikhailov, PRL 96, 018302 (2006) |
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