Stability of cluster solutions in a cooperative co

Authors: Juncheng Wei Matthias Winter

Publish Date: 2012/11/06

Volume: 68, Issue: 1-2, Pages: 1-39

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Abstract

We study a cooperative consumer chain model which consists of one producer and two consumers It is an extension of the Schnakenberg model suggested in Gierer and Meinhardt Kybernetik Berlin 1230–39 1972 and Schnakenberg J Theor Biol 81389–400 1979 for which there is only one producer and one consumer In this consumer chain model there is a middle component which plays a hybrid role it acts both as consumer and as producer It is assumed that the producer diffuses much faster than the first consumer and the first consumer much faster than the second consumer The system also serves as a model for a sequence of irreversible autocatalytic reactions in a container which is in contact with a wellstirred reservoir In the small diffusion limit we construct cluster solutions in an interval which have the following properties The spatial profile of the third component is a spike The profile for the middle component is that of two partial spikes connected by a thin transition layer The first component in leading order is given by a Green’s function In this profile multiple scales are involved The spikes for the middle component are on the small scale the spike for the third on the very small scale the width of the transition layer for the middle component is between the small and the very small scale The first component acts on the large scale To the best of our knowledge this type of spiky pattern has never before been studied rigorously It is shown that if the feedrates are small enough there exist two such patterns which differ by their amplitudesWe also study the stability properties of these cluster solutions We use a rigorous analysis to investigate the linearized operator around cluster solutions which is based on nonlocal eigenvalue problems and rigorous asymptotic analysis The following result is established If the timerelaxation constants are small enough one cluster solution is stable and the other one is unstable The instability arises through large eigenvalues of order O1 Further there are small eigenvalues of order o1 which do not cause any instabilities Our approach requires some new ideas i The analysis of the large eigenvalues of order O1 leads to a novel system of nonlocal eigenvalue problems with inhomogeneous Robin boundary conditions whose stability properties have been investigated rigorously ii The analysis of the small eigenvalues of order o1 needs a careful study of the interaction of two small length scales and is based on a suitable inner/outer expansion with rigorous error analysis It is found that the order of these small eigenvalues is given by the smallest diffusion constant epsilon 22

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