title: Ion acoustic waves in ultracold neutral plasmas.
abstract: We photoionize laser-cooled atoms with a laser beam possessing spatially periodic intensity modulations to create ultracold neutral plasmas with controlled density perturbations. Laser-induced fluorescence imaging reveals that the density perturbations oscillate in space and time, and the dispersion relation of the oscillations matches that of ion acoustic waves, which are long-wavelength, electrostatic, density waves.
authors.affiliation: Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, Texas 77005, USA.
authors.forename: J
authors.initials: J
authors.lastname: Castro
authors.forename: P
authors.initials: P
authors.lastname: McQuillen
authors.forename: T C
authors.initials: TC
authors.lastname: Killian