Recurrent Extreme Events in Spatially Extended Excitable Systems: Mechanisms of their Generation and Termination
1. Emergence and Propagation of Extreme Events
Extreme events are rare, aperiodic, recurrent events which have a large impact on dynamical systems. Real life examples of such events include extreme weather conditions (like floods, droughts and earthquakes), financial crashes, extreme medical conditions like epileptic siezures etc.
Identification of the common mathematical structure among these events and the various factors that cause such diverse phenomena forms the core of my research. Currently I am studying model excitable systems like FitzHugh-Nagumo Oscillators (which are known to generate extreme events) and trying to find signatures left by such events prior to their occurence and develop precurssors to these events.
2. Propagation of HarmFul Algal Blooms
Harmful Algal Blooms (HABs) occational phenomena occuring in oceans in which concentration of toxic algal species show an exceptional increase in concentration. This leads to sudden and severe loss of marine species in the affected area. This in turn leads to huge economic losses for the fishing industry (estimated annual cost of coping with such a disaster is estimaned from around 85 million to 4 billion US dollars).
Along with the experimental group in Wilhemshafen, we try to understand the emergence and propagation of HABs in marine ecosystem. Using experimental data from the labs, we are developing a sophisticated biological model that can help us understand the interplay of various physical (e.g. nutrient upwelling and ocean currents) and biological (e.g. inter-species competition and effect of toxins) processes that lead to such a disaster.
- Gorjao L. R., Saha A., Ansmann G., Feudel U., Lehnertz K., "Complexity and irreducibility of dynamics on networks of networks", submitted.
- Saha A., Feudel U., "Riddled basins of attraction in systems exhibiting extreme events", Chaos: An Interdisciplinary Journal of Nonlinear Science 28 (3), 033610.
- Saha A., Feudel U., "Intermittency in delay-coupled FitzHugh–Nagumo oscillators and loss of phase synchrony as its precursor", Indian Academy of Science Conference Series 1 (1), 163.
- Saha A., Feudel U., "Extreme events in FitzHugh-Nagumo oscillators coupled with two time delays", Phys. Rev. E 95, 062219 (2017)
- Shushko I, Avrutin V., Saha A., Banerjee B. and Gardini L., "Dangerous Bifurcations Revisited", Int. J. Bifurcation Chaos 26. 14 (2016) 1630040 [24 pages]
- Saha A. and Banerjee S., "Existence and Stability of Periodic Orbits in N-Dimensional Piecewise Linear Continuous Maps" (pre-print)
- Saha A. and Amritkar R. E., "Dependence of Synchronisation Frequency of Kuramoto oscillators on symmetry of intrinsic frequency in ring network", Pramana 83. 6 (2014): 945-953.
- Saha A. and Feudel U., "Emergence and Characteristics of Extreme Events in Delay-Coupled FitzHugh-Nagumo Oscillators", Perspectives in Nonlinear Dynamics, Berlin (2016).
- Saha A. and Feudel U., "Extreme Events in Delay-Coupled FitzHugh-Nagumo Oscillators", Dynamics Days Europe, Corfu (2016).
- Saha A. and Feudel U., "Extreme Events in Delay-Coupled Relaxation Oscillators", Extreme Events and Rogue Waves Seminar, Bad Honef (2016).
- Saha A. and Feudel U., "Propagation of Harmful Algal Blooms in Oceans: A Network Approach", CONFLOW: Complex network perspectives on flow systems, Potsdam (2015).
- Banerjee S. and Saha A., Avrutin, V., Gardini, G., "Dangerous Border Collision Bifurcation in Piecewise Smooth Maps", SIAM Conference on Dynamical Systems, Snowbird (2015).
- Saha A. and Banerjee S., "Existence and Stability of Periodic Orbits in Continuous, Non-Smooth 2-D Maps", Conference on Nonlinear Systems and Dynamics, Mohali (2015).
- Saha A. and Memmesheimer R. M., "Dynamical Stability Analysis of Neural Networks with Mixed Dissipation", Conference on Nonlinear Systems and Dynamics, Indore (2013).
2010-2015: BS-MS Dual Degree, Indian Institute of Science Education and Research Kolkata
- Kishore Vaigyanik Protsahan Yojana (KVPY) (2010-Present) Highest Scholarship for undergraduate studies in basic sciences in India. Awarded by Department of Science and Technology, Government of India.
- Indian Academy of Sciences Summer Research Fellowship (2012). Awarded by Indian Academy of Sciences, India.
- S. N. Bhatt Memorial Excellence Fellowship (2014).Awarded by International Centre for Theoretical Sciences, TIFR Bangalore.