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Fractal structures in the chaotic motion of charged particles in a magnetized plasma under the influence of drift waves

par Caroline CHAMPENOIS - publié le

séminaire du laboratoire
mercredi 6 décembre à 14:00

Ricardo L. Viana

Department of Physics, Federal University of Paraná, Curitiba, Paraná, Brazil

abstract :

Chaotic dynamics in open Hamiltonian dynamical systems typically presents a number of fractal structures in phase space derived from the interwoven structure of invariant manifolds and the corresponding chaotic saddle. These structures are thought to play an important role in the transport properties related to the chaotic motion. Such properties can explain some aspects of the non-uniform nature of the anomalous transport observed in magnetically confined plasmas. Accordingly we consider a simple theoretical model for the interaction of charged test particles with drift waves. We describe the exit basin structure of the corresponding chaotic orbit in phase space and interpret it in terms of the invariant manifold structure underlying chaotic dynamics. As a result, the exit basin boundary is shown to be a fractal curve, by direct calculation of its dimension and also by computation of the basin boundary entropy. Moreover, when there are more than two basins, we verify the existence of the Wada property, an extreme form of fractality.

contact : Fabrice Doveil

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