title: Plasma oscillations and expansion of an ultracold neutral plasma
abstract: We report the observation of plasma oscillations in an ultracold neutral plasma. With this collective mode we probe the electron density distribution and study the expansion of the plasma as a function of time. For classical plasma conditions, i.e., weak Coulomb coupling, the expansion is dominated by the pressure of the electron gas and is described by a hydrodynamic model. Discrepancies between the model and observations at low temperature and high density may be due to strong coupling of the electrons.
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8424, USA.
authors.initials: S
authors.lastname: Kulin
authors.initials: TC
authors.lastname: Killian
authors.initials: SD
authors.lastname: Bergeson
authors.initials: SL
authors.lastname: Rolston