Three-Dimensional Autonomous Pacemaker in the Photosensitive Belousov-Zhabotinsky medium

TL;DR

This paper reports the discovery of a stable three-dimensional autonomous pacemaker in the photosensitive Belousov-Zhabotinsky medium, combining experimental observations with numerical simulations to understand its behavior and stability.

Contribution

It introduces the first experimental observation of a 3D autonomous pacemaker in PBZR and validates it with numerical models, including stationary and breathing types.

Findings

Stable 3D chemical pacemaker observed experimentally.

Numerical simulations reproduce the pacemaker and reveal breathing oscillations.

Breathing pacemaker predicted numerically not yet observed experimentally.

Abstract

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. The 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. Stationary and breathing self-organized pacemakers have been found in these numerical simulations. In the latter case, both the radius of the scroll ring and the distance of its filament plane to the no-flux boundary after some transient undergo undamped stable limit cycle oscillations. So far, in contrary to their stationary counterpart, the numerically predicted breathing autonomous pacemaker has not been observed in the chemical experiment.