Homoclinic snaking of contact defects in reaction-diffusion equations

Fuente: arXiv
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Main Authors: Roberts, Timothy, Sandstede, Bjorn
Format: Preprint
Published: 2024
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author Roberts, Timothy
Sandstede, Bjorn
author_facet Roberts, Timothy
Sandstede, Bjorn
contents We apply spatial dynamical-systems techniques to prove that certain spatiotemporal patterns in reversible reaction-diffusion equations undergo snaking bifurcations. That is, in a narrow region of parameter space, countably many branches of patterned states coexist that connect at towers of saddle-node bifurcations. Our patterns of interest are contact defects, which are 1-dimensional time-periodic patterns with a spatially oscillating core region that at large distances from the origin in space resemble pure temporally oscillatory states and arise as natural analogues of spiral and target waves in one spatial dimension. We show that these solutions lie on snaking branches that have a more complex structure than has been seen in other contexts. In particular, we predict the existence of families of asymmetric travelling defect solutions with arbitrary background phase offsets, in addition to symmetric standing target and spiral patterns. We prove the presence of these additional patterns by reconciling results in classic ODE studies with results from the spatial-dynamics study of patterns in PDEs and using geometrical information contained in the stable and unstable manifolds of the background wavetrains and their natural equivariance structure.
format Preprint
id arxiv_https___arxiv_org_abs_2410_02621
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Homoclinic snaking of contact defects in reaction-diffusion equations
Roberts, Timothy
Sandstede, Bjorn
Dynamical Systems
Pattern Formation and Solitons
35B36, 35B40, 37L10
We apply spatial dynamical-systems techniques to prove that certain spatiotemporal patterns in reversible reaction-diffusion equations undergo snaking bifurcations. That is, in a narrow region of parameter space, countably many branches of patterned states coexist that connect at towers of saddle-node bifurcations. Our patterns of interest are contact defects, which are 1-dimensional time-periodic patterns with a spatially oscillating core region that at large distances from the origin in space resemble pure temporally oscillatory states and arise as natural analogues of spiral and target waves in one spatial dimension. We show that these solutions lie on snaking branches that have a more complex structure than has been seen in other contexts. In particular, we predict the existence of families of asymmetric travelling defect solutions with arbitrary background phase offsets, in addition to symmetric standing target and spiral patterns. We prove the presence of these additional patterns by reconciling results in classic ODE studies with results from the spatial-dynamics study of patterns in PDEs and using geometrical information contained in the stable and unstable manifolds of the background wavetrains and their natural equivariance structure.
title Homoclinic snaking of contact defects in reaction-diffusion equations
topic Dynamical Systems
Pattern Formation and Solitons
35B36, 35B40, 37L10
url https://arxiv.org/abs/2410.02621