Sumana Dutta | Searcharxiv

arXiv2024

Spiral, Core-defect and Wave break in a modified Oregonator Model

Target waves and spiral waves were discovered in the Belousov-Zhabotinsky (BZ) reaction around 50 years ago. Many biological systems demonstrate such rotating spiral patterns. Spiral waves are widely encountered in the glycolytic activity of yeast and cardiac and neuronal tissues. In the cardiac system, the spiral waves and their three dimensional counterparts, the scroll waves are the cause of arrhythmia. These waves are also widely studied in the experimental BZ reaction as a table-top model of the cardiac system. To understand the underlying physics or chemistry of the system, the Oregonator model is considered in correlation to the BZ reaction system. In this study, starting from the same FKN mechanism, we slightly modify the original Oregonator model. We present a three-variable model that can be called a modified Oregonator model in which we observe the presence of the spiral, spiral defect, and spiral breakup by tuning the parameters.

nlin.PS↗

arXiv2021

Interaction of multiple spiral rotors in a reaction-diffusion system

Rotors of reaction and diffusion, that revolve around a circular singularity, and the corresponding spiral wave activity around it, influence the nature of several excitable media. Their dynamics are known to be affected by target waves and external gradients. When the core of two spirals come very close to each other, they could either repel or attract, depending on their relative chirality and the distance separating them. Multiple pairs of spiral waves, in close vicinity, could alter the paths of the individual rotors. A single spiral core, will be influenced most by the rotor closest to it, or linked to it by a common wave. If within a limiting distance, they would attract each other, and annihilate. Else, they will push each other away, until they reach a critical distance, beyond which, all interactions seem to cease. We have carried out numerical simulations based on a reaction-diffusion model to show the possible interactions of multiple spiral rotors. We are able to find a quantitative measurement of the distances determining the kind of interaction. Some unique dynamics is also unraveled. Experiments with the Belousov-Zhabotinsky reaction have successfully demonstrated the validity of our numerical results.

nlin.PS↗