Localized Patterns in Periodically Forced Systems: II. Patterns with Non-Zero Wavenumber

TL;DR

This paper investigates localized oscillatory patterns, called oscillons, in a PDE model with periodic forcing, focusing on non-zero wavenumber patterns and deriving amplitude equations that match experimental observations.

Contribution

It derives coupled forced complex Ginzburg-Landau equations from a PDE model with periodic forcing, revealing localized solutions and snaking behavior relevant to experiments.

Findings

Localized solutions exhibit snaking behavior.

Amplitude equations accurately predict oscillons near onset.

Model results align with experimental Faraday wave observations.

Abstract

In pattern-forming systems, localized patterns are readily found when stable patterns exist at the same parameter values as the stable unpatterned state. Oscillons are spatially localized, time-periodic structures, which have been found experimentally in systems that are driven by a time-periodic force, for example, in the Faraday wave experiment. This paper examines the existence of oscillatory localized states in a PDE model with single frequency time dependent forcing, introduced in [A. M. Rucklidge and M. Silber, SIAM J. Appl. Math., 8 (2009), pp. 298-347, arXiv:0805.0878] as a phenomenological model of the Faraday wave experiment. We choose parameters so that patterns set in with non-zero wavenumber (in contrast to [A. S. Alnahdi, J. Niesen and A. M. Rucklidge, SIAM J. Appl. Dyn. Syst., 13 (2014), pp. 1311-1327, arXiv:1312.2773]). In the limit of weak damping, weak detuning, weak forcing, small group velocity, and small amplitude, we reduce the model PDE to the coupled forced complex Ginzburg-Landau equations. We find localized solutions and snaking behaviour in the coupled forced complex Ginzburg-Landau equations and relate these to oscillons that we find in the model PDE. Close to onset, the agreement is excellent. The periodic forcing for the PDE and the explicit derivation of the amplitude equations make our work relevant to the experimentally observed oscillons.