Castro, J.McQuillen, P.Killian, T.C.2012-11-262012-11-262010Castro, J., McQuillen, P. and Killian, T.C.. "Ion Acoustic Waves in Ultracold Neutral Plasmas." <i>Physical Review Letters,</i> 105, (2010) American Physical Society: 65004. http://dx.doi.org/10.1103/PhysRevLett.105.065004.https://hdl.handle.net/1911/68395We 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.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1103/PhysRevLett.105.065004