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DY: Fachverband Dynamik und Statistische Physik
DY 22: Posters I
DY 22.36: Poster
Wednesday, March 28, 2012, 17:00–19:00, Poster A
Surfactant-induced gradients in the 3D Belousov-Zhabotunsky reaction — •Dennis Kupitz1, Sergio Alonso2, Markus Bär2, and Marcus Hauser1 — 1Abteilung Biophysik, Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Germany — 2Physikalisch-Technische Bundesanstalt, Fachbereich 8.4, Berlin, Germany
Scroll waves are prominent patterns formed in 3D excitable media, and they have been found to be at the basis of some types of cardiac arrhythmias. Experimentally, scroll waves dynamics is often studied by optical tomography in the Belousov-Zhabotinsky reaction, which produces CO2 as an undesired product. Addition of small concentrations of a surfactant is a popular method to suppress or retard CO2 bubble formation. We report that in closed reactors even these low concentrations of surfactants are sufficient to generate vertical gradients of excitability which are due to gradients in CO2 concentration. In reactors open to the atmosphere such gradients can be avoided. Gradients are shown to induce a twist onto vertically oriented scroll waves, while a twist is absent in scroll waves in a gradient-free medium. The effects of the CO2 gradients are explained by a numerical study, where we modified the Oregonator model to account for the production of CO2 and for its advection against the direction of gravity. The numerical simulations confirm the role of solubilized CO2 as the source of the vertical gradients of excitability in reactors closed to the atmosphere.
[1] D. Kupitz, S. Alonso, M. Bär, M.J.B. Hauser, Phys. Rev. E 84, 056210 (2011).