Smoothing and Global Attractors for the Hirota-Satsuma System on the Torus

TL;DR

This paper studies the Hirota-Satsuma system on a torus, establishing smoothing estimates influenced by the coupling parameter and proving the existence of a global attractor for the forced and damped system.

Contribution

It provides new smoothing estimates for the Hirota-Satsuma system and demonstrates the existence of a global attractor under forcing and damping conditions.

Findings

Smoothing estimates depend on the arithmetic nature of the coupling parameter.

Existence of a smooth global attractor in the energy space.

Analysis of resonant sets influences smoothing properties.

Abstract

We consider the Hirota-Satsuma system, a coupled KdV-type system, with periodic boundary conditions. The first part of the paper concerns with the smoothing estimates for the system. More precisely, it is shown that, for initial data in a Sobolev space, the difference of the nonlinear and linear evolutions lies in a smoother space. The smoothing gain we obtain depends very much on the arithmetic nature of the coupling parameter $a$ which determines the structure of the resonant sets in the estimates. In the second part, we address the forced and damped Hirota-Satsuma system and obtain counterpart smoothing estimates. As a consequence of these estimates, we prove the existence and smoothness of a global attractor in the energy space.