Effect of Particle Number Density on Wave Dispersion in a Two-Dimensional Yukawa System**Supported by the National Natural Science Foundation of China under Grant Nos 11675261 and 21403297, and the Scientific Research Foundation of Ludong University under Grant No LY2014010.

Abstract

Effect of the particle number density on the dispersion properties of longitudinal and transverse lattice waves in a two-dimensional Yukawa charged-dust system is investigated using molecular dynamics simulation. The dispersion relations for the waves are obtained. It is found that the frequencies of both the longitudinal and transverse dust waves increase with the density and when the density is sufficiently high a cutoff region appears at the short wavelength. With the increase of the particle number density, the common frequency tends to increase, and the sound speed of the longitudinal wave also increases, but that of the transverse wave remains low.