We develop the geometrical, analytical, and computational framework for reactive island theory for three degrees-of-freedom time-independent Hamiltonian systems. In this setting, the dynamics occurs in a 5-dimensional energy surface in phase space and is governed by four-dimensional stable and unstable manifolds of a three-dimensional normally hyperbolic invariant sphere. The stable and unstable manifolds have the geometrical structure of spherinders and we provide the means to investigate the ways in which these spherinders and their intersections determine the dynamical evolution of trajectories. This geometrical picture is realized through the computational technique of Lagrangian descriptors. In a set of trajectories, Lagrangian descriptors allow us to identify the ones closest to a stable or unstable manifold. Using an approximation of the manifold on a surface of section we are able to calculate the flux between two regions of the energy surface.
Bibliographical noteFunding Information:
The authors would like to acknowledge the financial support provided by the EPSRC, United Kingdom Grant No. EP/P021123/1 and the Office of Naval Research, United States Grant No. N00014-01-1-0769 .
© 2021 Elsevier B.V.
- phase space
- Hamiltonian systems
- stable and unstable manifolds
- normally hyperbolic invariant manifolds
- reactive islands
- Lagrangian descriptors