An experimental route to spatiotemporal chaos in an extended 1D oscillators array

TL;DR

This paper experimentally investigates the transition to spatiotemporal chaos in a 1D thermoconvective system, revealing a sequence of pattern instabilities, synchronization transitions, and coherence domains as the driving force increases.

Contribution

It provides the first detailed experimental evidence of the route to spatiotemporal chaos in a large 1D array of oscillators, highlighting the role of synchronization and bifurcations.

Findings

Identification of irregular clusters with variable coherence.

Observation of a supercritical bifurcation to a beating regime.

Detection of phase-like synchronization transitions.

Abstract

We report experimental evidence of the route to spatiotemporal chaos in a large 1D-array of hotspots in a thermoconvective system. Increasing the driving force, a stationary cellular pattern becomes unstable towards a mixed pattern of irregular clusters which consist of time-dependent localized patterns of variable spatiotemporal coherence. These irregular clusters coexist with the basic cellular pattern. The Fourier spectra corresponding to this synchronization transition reveals the weak coupling of a resonant triad. This pattern saturates with the formation of a unique domain of great spatiotemporal coherence. As we further increase the driving force, a supercritical bifurcation to a spatiotemporal beating regime takes place. The new pattern is characterized by the presence of two stationary clusters with a characteristic zig-zag geometry. The Fourier analysis reveals a stronger coupling and enables to find out that this beating phenomena is produced by the splitting of the fundamental spatiotemporal frequencies in a narrow band. Both secondary instabilities are phase-like synchronization transitions with global and absolute character. Far beyond this threshold, a new instability takes place when the system is not able to sustain the spatial frequency splitting, although the temporal beating remains inside these domains. These experimental results may support the understanding of other systems in nature undergoing similar clustering processes.