Hits:

Indexed by:期刊论文

Date of Publication:2012-07-01

Journal:PHYSICS OF PLASMAS

Included Journals:SCIE、EI

Volume:19

Issue:7

ISSN No.:1070-664X

Abstract:The dispersion relations of the externally and thermally (naturally) excited dust lattice modes (both longitudinal and transverse) in two-dimensional Debye-Yukawa complex plasma crystals are investigated. The dispersion relations are calculated numerically by taking the neutral gas damping effects into account and the numerical results are in agreement with the experimental data given by Nunomura et al. [Phys. Rev. E 65, 066402 (2002)]. It is found that for the mode excited by an external disturbance with a real frequency, the dispersion properties are changed at a critical frequency near where the group velocity of the mode goes to zero. Therefore, the high frequency branch with negative dispersion cannot be reached. In contrast, for the thermally excited mode, the dispersion curve can extend all the way to the negative dispersion region, while a "cut-off' wave number exists at the long wavelength end of the dispersion in the transverse mode. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4740035]