“Spatiotemporal patterns in the Bär Model 2D induced by concentration-dependent diffusivities”

PAULA BERGERO; EDUARDO ELÍAS MOLA; ISABEL MARÍA IRURZUN

Mar del Plata

Workshop; Pan American Scientific Institute “From Disordered systems to Complex systems”; 2006

A wide variety of physical, biological and chemical contexts may be treated as  excitable media which support wave propagation.  Spatiotemporal pattern formation in these media is of particular interest. Patterns like circular  waves, spiral waves, turbulence and  the respective transitions could be modeled by reaction-diffusion  model. A considerable amount of real reaction-diffusion systems present inhomogeneities arising from situations like medium surface properties,  intermolecular forces or active transport of metabolites.   In most of the work, the inhomogeneities appears in the kinetic  terms of the model rather than in the diffusion coefficients. However,  transport gradients in excitable media could also be used to create and select pattern formation. In this work, we have studied the  Bär model,  a  modified  version of the FitzHugh-Nagumo model to describe the autocatalitic chemical reaction in CO oxidation on Pt(110).  We have investigated the effects of diffusivity on pattern formation in 2D, proposing the local diffusion coefficients  to be functional relationships  with the local  concentration of a chemical reactant.