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A "transitory'' dynamical system is one whose time-dependence is
confined to a compact interval. In this paper we show how to quantify transport between Lagrangian coherent
structures for the Hamiltonian case. This quantification requires knowing only the relevant
heteroclinic orbits on the intersection of invariant manifolds of ``forward" and ``backward"
hyperbolic orbits. These manifolds can be easily computed by leveraging the autonomous nature of the
vector fields on either side of the time-dependent transition. As examples we consider a fluid flow
in a rotating double-gyre configuration and a simple model of a resonant particle accelerator. We
compare our results to those obtained using finite-time Lyapunov exponents and to adiabatic theory,
discussing the benefits and limitations of each method.
The figure shows the lobes constructed from the images of the unstable manifold of a resonance in the past, with the stable manifolds
of a resonance at the current time for a simple Hamilitonian model of an accelerating potential well.
More details are in the paper Transport in Transitory Dynamical Systems.
This research, and much of the research listed below has received support from the National Science Foundation,
most recently under grants DMS-0202032 and DMS-0707659.
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