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Inwardly rotating spirals in nonuniform excitable media
Xiang Gao1, Xia Feng, Mei-chun Cai
1Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, China.
Summary
Inwardly rotating spirals (IRSs) were observed for the first time in a non-uniform excitable medium. These spirals feature excitation propagating inwards towards the spiral tip.
Area of Science:
- Nonlinear dynamics
- Excitable media
- Pattern formation
Background:
- Inwardly rotating spirals (IRSs) are phenomena of great interest, observed previously in oscillatory reaction-diffusion systems.
- IRSs have not been reported in planar excitable media until this study.
Purpose of the Study:
- To investigate the occurrence of IRSs in a non-uniform planar excitable medium.
- To explore the influence of varying excitability and inhomogeneity on spiral wave dynamics.
Main Methods:
- Numerical simulations using a simple FitzHugh-Nagumo model.
- Investigated a non-uniform excitable medium composed of an inner disk and an outer ring with differing excitabilities.
Main Results:
- Successfully observed IRSs in the simulated non-uniform excitable medium.
- The occurrence of IRSs was found to be dependent on the medium's excitability and the degree of inhomogeneity.
- Demonstrated that in these IRSs, excitation propagates inwardly towards the geometrical spiral tip.
Conclusions:
- This study reports the first observation of IRSs in a planar non-uniform excitable medium.
- The findings highlight the role of medium properties, specifically excitability and inhomogeneity, in the emergence of complex spiral wave patterns.
- The results contribute to understanding pattern formation in biological and chemical systems.
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