title: Phonon spectrum in a plasma crystal.
abstract: The Fourier spectra of longitudinal and transverse waves corresponding to random particle motion were measured in a two-dimensional plasma crystal. The crystal was composed of negatively charged microspheres immersed in a plasma at a low gas pressure. The phonons were found to obey a dispersion relation that assumes a Yukawa interparticle potential. The crystal was in a nonthermal equilibrium, nevertheless phonon energies were almost equally distributed with respect to wave number over the entire first Brillouin zone.
authors.affiliation: Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nunomura
authors.forename: J
authors.initials: J
authors.lastname: Goree
authors.forename: S
authors.initials: S
authors.lastname: Hu
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: A
authors.initials: A
authors.lastname: Bhattacharjee
authors.forename: K
authors.initials: K
authors.lastname: Avinash