Dynamical organization of recollisions by a family of invariant tori

TL;DR

This paper investigates the phase space structures, specifically invariant tori and their manifolds, that organize electron recollision trajectories in atoms under strong laser fields, providing insight into the recollision dynamics.

Contribution

It identifies and computes a family of invariant tori and their manifolds that organize recollision trajectories, revealing the geometric structure underlying recollision processes.

Findings

Invariant tori organize recollision trajectories.

Stable and unstable manifolds structure phase space dynamics.

Recollision pathways are governed by these invariant structures.

Abstract

We consider the motion of an electron in an atom subjected to a strong linearly polarized laser field. We identify the invariant structures organizing a very specific subset of trajectories, namely recollisions. Recollisions are trajectories which first escape the ionic core (i.e., ionize) and later return to this ionic core, for instance, to transfer the energy gained during the large excursion away from the core to bound electrons. We consider the role played by the directions transverse to the polarization direction in the recollision process. We compute the family of two-dimensional invariant tori associated with a specific hyperbolic-elliptic periodic orbit and their stable and unstable manifolds. We show that these manifolds organize recollisions in phase space.