Heteroclinic for a 6-dimensional reversible system occuring in orthogonal domain walls in convection
Gérard Iooss
TL;DR
The paper proves the existence, local uniqueness, and analyticity of a heteroclinic connection between orthogonal-convection roll states in a six-dimensional reversible normal-form system derived from Benard-Rayleigh convection. By constructing a 5D invariant manifold on which a 3D unstable manifold from M_- intersects a 3D stable manifold from M_+, the authors establish transversal intersection and derive precise asymptotics for the heteroclinic orbit, with the heteroclinic shown to depend analytically on the parameters (notably g). A detailed linearized analysis along the heteroclinic yields Fredholm properties and a one-dimensional kernel, enabling persistence results under reversible perturbations and linking to orthogonal domain walls in convection. The approach hinges on careful coordinate changes, a first-integral constraint, integral formulations, and fixed-point arguments, culminating in a rigorous, parameter-analytic heteroclinic curve and a framework for studying perturbations. These results provide a rigorous foundation for domain-wall persistence and offer sharp estimates essential for applications to convection phenomena.
Abstract
A six-dimensional reversible normal form system occurs in B{é}nard-Rayleigh convection between parallel planes, when we look for domain walls intersecting orthogonally (see Buffoni et al [1]). On the truncated system, we prove analytically the existence, local uniqueness, and analyticity in parameters, of a heteroclinic connection between two equilibria, each corresponding to a system of convective rolls. We prove that the 3-dimensional unstable manifold of one equilibrium, intersects transversally the 3-dimensional stable manifold of the other equilibrium, both manifolds lying on a 5-dimensional invariant manifold. We also study the linearized operator along the heteroclinic, allowing to prove (in [9]) the persistence under reversible perturbation, of the heteroclinic obtained in [1].
