Stationary spatial structures in reaction-subdiffusion

Abstract

We discuss stationary concentrations of reactants in an A + B -> 0 reaction under subdiffusion and show that they are described by stationary reaction-diffusion equations with a nonlinear diffusion term. We consider stationary profiles of reactants' concentrations and of reaction zones in a flat subdiffusive medium fed by reactants of both types on its both sides (a subdiffusive gel reactor). The behavior of the concentrations and of the reaction intensity in subdiffusion differs strikingly from those in simple diffusion. The most important differences correspond to the existence of accumulation and depletion zones close to the boundaries and to non-monotonous behavior of the reaction intensity with respect to the strength of the minor source. The implications of these results for other situations are also discussed.