Optimal perturbation for enhanced chaotic transport (Q1779763)

The author considers a perturbed autonomous Hamiltonian system as a model of a fluid flow. In the two-dimensional case, it is assumed that the nonperturbed system has a separatrice joining two hyperbolic saddle rest points. The geometry of separatrices after a perturbation determines the so-called ``flux across a separatrice''. The problem is to determine perturbations that are optimal in the sense of the resulting flux. A similar problem is studied in the three-dimensional case. Two examples (planar cellular flow and Hill's spherical vortex) are analyzed.