Berlin 2015 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 23: Reaction-Diffusion Systems

DY 23.4: Vortrag

Dienstag, 17. März 2015, 15:15–15:30, BH-N 243

Three-Dimensional Autonomous Pacemaker in Excitable Media — •Arash Azhand, Jan F. Totz, and Harald Engel — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

In experiments with the photosensitive Belousov-Zhabotinsky reaction (PBZR) we found a stable three-dimensional organizing center that periodically emits trigger waves of chemical concentration. Our experiments are performed in a parameter regime with negative line tension using an open gel reactor to maintain stationary non-equilibrium conditions. The observed periodic wave source is formed by a scroll ring stabilized due to its interaction with a no-flux boundary.

Sufficiently far from the boundary, the scroll ring expands and undergoes the negative line tension instability before it finally develops into scroll wave turbulence. Our experimental results are reproduced by numerical integration of the modified Oregonator model for the PBZR. In the numerical simulations besides stationary also breathing self-organized pacemakers have been found where both the radius of the scroll ring and the distance of its filament plane to the no-flux boundary undergo stable limit cycle oscillations.

[1] Y. Kuramoto, Chemical Oscillations, Waves, and Turbulence (Dover Publications, 2003)

[2] M. Stich, I. Ipsen, and A.S. Mikhailov, Phys. Rev. Lett. 86, 4406 (2001)

[2] A. Azhand, J. F. Totz, and H. Engel, EPL 108, 10004 (2014)