title: Ion velocity distribution function investigated inside an unstable magnetized plasma exhibiting a rotating nonlinear structure.
abstract: The frequent situation where a strongly nonlinear rotating structure develops in a linear magnetized plasma column is investigated experimentally with emphasis on the ion velocity distribution function (IVDF). Most often, a mode m=2 appears exhibiting a large density and potential perturbation with angular frequency slightly above the ion cyclotron frequency. For the first time the spatiotemporal evolution of the IVDF is studied using time-resolved laser induced fluorescence to explore the ion's interaction with the nonlinear wave propagating inside the column and at the origin of plasma transport outside the limiter. The ion fluid exhibits an alternance from azimuthal to radial velocity due to the electric field inside the rotating structure. A fluid model also allows us to locally reconstruct the self-consistent electric field evolution which contradicts all existing theories.
authors.affiliation: PIIM, UMR6633 CNRS/Université de Provence, case 321, centre universitaire de Saint-Jérôme, Marseille, France.
authors.forename: C
authors.initials: C
authors.lastname: Rebont
authors.forename: N
authors.initials: N
authors.lastname: Claire
authors.forename: Th
authors.initials: T
authors.lastname: Pierre
authors.forename: F
authors.initials: F
authors.lastname: Doveil