Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 15: Reaction Diffusion Systems
DY 15.1: Vortrag
Mittwoch, 24. März 2010, 10:00–10:15, H46
Excitation patterns in inhomogeneous media from the FitzHugh-Nagumo equations and the Belousov-Zhabotinsky reaction — •Claudia Lenk1, Mario Einax1, J. Michael Koehler1, and Philipp Maass1,2 — 1Institut für Physik, Technische Universität Ilmenau, 98684 Ilmenau, Germany. — 2Fachbereich Physik, Universität Osnabrück, 49069 Osnabrück, Germany.
Spatial inhomogeneities of the control parameters in reaction-diffusion systems play a crucial role for the occurrence of self-excitatory sources like spiral waves and ectopic foci. Here we present a systematic analysis of locally reduced resting state stabilities and increased excitabilities in terms of dynamical phase diagrams based on the FitzHugh-Nagumo equations. These phase diagrams specify regions of spiral wave and ectopic activity in dependence of the size and strengths of the modified regions. We further study the mutual disturbance of wavefronts that emanate from two pacemakers and propagate in regions connected by a small bridge. In particular we address the question how this disturbance can lead to fibrillatory states. Our results are partly compared to experiments that we performed for the Belousov-Zhabotinsky reaction in a silica gel with a spatially inhomogeneous catalyst (Ferroin) distribution. In these experiments the coupling of catalyst spots arranged in 4x4 arrays is investigated in dependence of the spot size and spot distance.