Extreme events in two-coupled chaotic oscillators

TL;DR

This study investigates the emergence and mechanisms of extreme events in a system of two coupled R"ossler oscillators, revealing their occurrence in various observables and analyzing their statistical properties using extreme value theory.

Contribution

It uncovers the mechanisms behind extreme events in coupled chaotic oscillators and applies generalized extreme value theory to analyze their statistics.

Findings

Extreme events occur in average velocity, synchronization error, and transverse variables.

On-off intermittency is crucial for the genesis of extreme events.

Extreme value distributions fit the observed extreme events data.

Abstract

Since 1970, the R\"ossler system has remained as a considerably simpler and minimal dimensional chaos serving system. Unveiling the dynamics of a system of two coupled chaotic oscillators that leads to the emergence of extreme events in the system is an engrossing and crucial scientific research area. Our present study focuses on the emergence of extreme events in a system of diffusively and bidirectionally two coupled R\"ossler oscillators and unraveling the mechanism behind the genesis of extreme events. We find the appearance of extreme events in three different observables: average velocity, synchronization error, and one transverse directional variable to the synchronization manifold. The emergence of extreme events in average velocity variables happens due to the occasional in-phase synchronization. The on-off intermittency plays for the crucial role in the genesis of extreme events in the synchronization error dynamics and in the transverse directional variable to the synchronization manifold. The bubble transition of the chaotic attractor due to the on-off intermittency is illustrated for the transverse directional variable. We use generalized extreme value theory to study the statistics of extremes. The extreme events data sets concerning the average velocity variable follow generalized extreme value distribution. The inter-event intervals of the extreme events in the average velocity variable spread well exponentially. The upshot of the interplay between the coupling strength and the frequency mismatch between the system oscillators in the genesis of extreme events in the coupled system is depicted numerically.