Alladi Ramakrishnan Hall

Understanding ``Far From Equilibrium Phenomenon": Dynamics and control of spiral and scroll waves

Sumana Dutta

Department of Chemistry, Indian Institute of Technology-Guwahati, Guwahati 781039, India

Waves and vortices form spontaneously in various excitable media. Spirals and scrolls are wave-forms found in several biological systems, more importantly, in cardiac tissues, where they are oftentimes the cause of fatal cardiac arrest. Such kinds of waves are also seen in reaction diffusion systems. While the length and time scales of these two systems are very different, there is an inherent similarity in the dynamics of the nonlinear wave-forms. We use the Belousov-Zhabotinsky reaction as a laboratory model to study the formation and interaction of spiral and scroll waves and try to control them using external field gradients. Another interesting phenomenon is the pinning of scroll waves by which they get attached to heterogeneous obstacles that remarkably increase their life-times. We have been successfully able to unpin these pinned scroll waves by the employment of an external stimulus, like electromagnetic field and thermal gradient. Theoretical analysis of the results and observations help us understand the filament dynamics better.