Dust density waves in a complex plasma layer

Abstract

Modifications of dust density waves in a complex plasma layer imbedded in a bulk of electron ion plasmas are studied. In view of laboratory experiments, we consider a layer of finite thickness to be able to examine various cases of interest. Different electron and ion populations inside and outside of the complex plasma layer are assumed. It is found that (i) the geometric factor leads to a splitting of the surface dust-density modes in a specific region of wavenumbers and the appearance of a backward surface mode in case of a thin layer (d∼λD); (ii) due to spatial restriction of a complex plasma, the bulk dust-acoustic mode appears to have the lowest cutoff frequency, whose value is strongly dependent on the ratio between the screening length and the thickness of the layer. Observations of the features discussed can be used for complex plasma diagnostics.