Chimera states in ensembles of excitable FitzHugh-Nagumo systems

TL;DR

This paper investigates the emergence of coherence-resonance chimera states in ensembles of FitzHugh-Nagumo systems, revealing that specific coupling, not noise alone, induces these states and identifying a new chimera state in excitable regimes.

Contribution

It demonstrates that coupling, rather than noise, is responsible for chimera states and introduces a new chimera state in excitable FitzHugh-Nagumo systems.

Findings

Coupling induces coherence-resonance chimera states without noise.

A new chimera state is identified in excitable regimes.

Noise enhances the stability of these chimera states near bifurcations.

Abstract

An ensemble of nonlocally coupled excitable FitzHugh-Nagumo systems is studied. In the presence of noise the explored system can exhibit a special kind of chimera states called coherence-resonance chimera. As previously thought, noise plays principal role in forming these structures. It is shown in the present paper that these regimes appear because of the specific coupling between the elements. The action of coupling involve a spatial wave regime, which occurs in ensemble of excitable nodes even if the noise is switched off. In addition, a new chimera state is obtained in an excitable regime. It is shown that the noise makes this chimera more stable near an Andronov-Hopf bifurcation.