title: Spatial instabilities in a cloud of cold atoms.
abstract: Cold atomic clouds have been shown to have some similarities with plasmas. Previous studies showed that such clouds exhibit instabilities induced by long-range interactions. However, they did not describe the spatial properties of the dynamics. In this paper, we study experimentally the spatial nature of stochastic instabilities, and we find out that the dynamics is localized. Data are analyzed both in the spectral domain and in the spatial domain (principal component analysis). Both methods fail to describe the dynamics in terms of eigenmodes, showing that space and time are not separable.
authors.affiliation: Université Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, 59000 Lille, France.
authors.forename: Rudy
authors.initials: R
authors.lastname: Romain
authors.affiliation: Université Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, 59000 Lille, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Jallageas
authors.affiliation: Université Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, 59000 Lille, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Verkerk
authors.affiliation: Université Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, 59000 Lille, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hennequin