title: Control of Hamiltonian chaos as a possible tool to control anomalous transport in fusion plasmas.
abstract: It is shown that a relevant control of Hamiltonian chaos is possible through suitable small perturbations whose form can be explicitly computed. In particular, it is possible to control (reduce) the chaotic diffusion in the phase space of a Hamiltonian system with 1.5 degrees of freedom which models the diffusion of charged test particles in a turbulent electric field across the confining magnetic field in controlled thermonuclear fusion devices. Though still far from practical applications, this result suggests that some strategy to control turbulent transport in magnetized plasmas, in particular, tokamaks, is conceivable. The robustness of the control is investigated in terms of a departure from the optimum magnitude, of a varying cutoff at large wave vectors, and of random errors on the phases of the modes. In all three cases, there is a significant region of maximum efficiency in the vicinity of the optimum control term.
authors.affiliation: Facoltà di Ingegneria, Università di Firenze, via S. Marta, I-50129 Florence, Italy. ciraolo@arcetri.astro.it
authors.forename: Guido
authors.initials: G
authors.lastname: Ciraolo
authors.forename: Françoise
authors.initials: F
authors.lastname: Briolle
authors.forename: Cristel
authors.initials: C
authors.lastname: Chandre
authors.forename: Elena
authors.initials: E
authors.lastname: Floriani
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lima
authors.forename: Michel
authors.initials: M
authors.lastname: Vittot
authors.forename: Marco
authors.initials: M
authors.lastname: Pettini
authors.forename: Charles
authors.initials: C
authors.lastname: Figarella
authors.forename: Philippe
authors.initials: P
authors.lastname: Ghendrih