86 citations · 692 across the 44 of their papers we have counts for
18 papers · 1 filter
Study on creation and destruction of transport barriers via effective safety factors for energetic particles
Shun Ogawa, Xavier Leoncini, Guilhem Dif-Pradalier +1
Charged particles with low kinetic energy move along magnetic field lines, but so do not energetic particles. We investigate the topological structure changes in the phase space of…
Full particle orbit effects in regular and stochastic magnetic fields
Shun Ogawa, Benjamin Cambon, Xavier Leoncini +4
We present a numerical study of charged particle motion in a time-independent magnetic field in cylindrical geometry. The magnetic field model consists of an unperturbed reversed-s…
Anomalous transport and observable average in the standard map
Lydia Bouchara, Ouerdia Ourrad, Sandro Vaienti +1
The distribution of finite time observable averages and transport in low dimensional Hamiltonian systems is studied. Finite time observable average distributions are computed, from…
Mixing properties in the advection of passive tracers via recurrences and extreme value theory
Davide Faranda, Xavier Leoncini, Sandro Vaienti
In this paper we characterize the mixing properties in the advection of passive tracers by exploiting the extreme value theory for dynamical systems. With respect to classical tech…
Chaotic motion of charged particles in toroidal magnetic configurations
Benjamin Cambon, Xavier Leoncini, Michel Vittot +2
We study the motion of a charged particle in a tokamak magnetic field and discuss its chaotic nature. Contrary to most of recent studies, we do not make any assumption on any const…
Directed transport in a spatially periodic potential under periodic non-biased forcing
Xavier Leoncini, Anatoly Neishtadt, Alexei Vasiliev
Transport of a particle in a spatially periodic harmonic potential under the influence of a slowly time-dependent unbiased periodic external force is studied. The equations of moti…
Ergodicité, collage et transport anomal
Xavier Leoncini, Cristel Chandre, Ouerdia Ourrad
Nous nous intéressons à la convergence vers sa moyenne spatiale ergodique de la moyenne temporelle d'une observable d'un flow hamiltonien à un degré et demi de liberté avec espace…
Targeted mixing in an array of alternating vortices
Romain Bachelard, Tounsia Benzekri, Cristel Chandre +2
Transport and mixing properties of passive particles advected by an array of vortices are investigated. Starting from the integrable case, it is shown that a special class of pertu…
Control of chaotic advection
Tounsia Benzekri, Cristel Chandre, Xavier Leoncini +4
A method of chaos reduction for Hamiltonian systems is applied to control chaotic advection. By adding a small and simple term to the stream function of the system, the constructio…
Stabilizing the intensity of a wave amplified by a beam of particles
Romain Bachelard, Andrea Antoniazzi, Cristel Chandre +3
The intensity of an electromagnetic wave interacting self-consistently with a beam of charged particles as in a free electron laser, displays large oscillations due to an aggregate…
Evidence of fractional transport in point-vortex flow
Xavier Leoncini, Leonid Kuznetsov, George M. Zaslavsky
Advection properties of passive particles in flows generated by point vortices are considered. Transport properties are anomalous with characteristic transport exponent …
Chaotic Jets
Xavier Leoncini, George M. Zaslavsky
The problem of characterizing the origin of the non-Gaussian properties of transport resulting from Hamiltonian dynamics is addressed. For this purpose the notion of chaotic jet is…
From chaos of lines to Lagrangian structures in flux conservative fields
Xavier Leoncini, Olivier Agullo, Magali Muraglia +1
A numerical method is proposed in order to track field lines of three-dimensional divergence free fields. Field lines are computed by a locally valid Hamiltonian mapping, which is…
Reducing or enhancing chaos using periodic orbits
Romain Bachelard, Cristel Chandre, Xavier Leoncini
A method to reduce or enhance chaos in Hamiltonian flows with two degrees of freedom is discussed. This method is based on finding a suitable perturbation of the system such that t…
Chaotic advection and targeted mixing
Tounsia Benzekri, Cristel Chandre, Xavier Leoncini +2
The advection of passive tracers in an oscillating vortex chain is investigated. It is shown that by adding a suitable perturbation to the ideal flow, the induced chaotic advection…
Anomalous transport in Charney-Hasegawa-Mima flows
Xavier Leoncini, Olivier Agullo, Sadruddin Benkadda +1
Transport properties of particles evolving in a system governed by the Charney-Hasegawa-Mima equation are investigated. Transport is found to be anomalous with a non linear evoluti…
Jets, Stickiness and Anomalous Transport
Xavier Leoncini, George M. Zaslavsky
Dynamical and statistical properties of the vortex and passive particle advection in chaotic flows generated by four and sixteen point vortices are investigated. General transport…
Chaotic Advection near 3-Vortex Collapse
X. Leoncini, L. Kuznetsov, G. M. Zaslavsky
Dynamical and statistical properties of tracer advection are studied in a family of flows produced by three point-vortices of different signs. A collapse of all three vortices to a…