Excitation of surface plasma waves by a density modulated electron beam at a conductor-dusty plasma interface

A density modulated electron beam propagating through a conductor-dusty plasma interface drives electromagnetic surface plasma waves (SPWs) to instability via Cerenkov and cyclotron interaction. The SPWs propagate across an external magnetic field parallel to the interface. Numerical calculations of the growth rate and unstable mode frequencies have been carried out for the typical parameters of the SPWs. The frequency and the growth rate of the unstable wave instability increase with the relative density of negatively charged dust grains delta (=n(io)/n(eo), where n(io) is the ion plasma density and n(eo) is the electron plasma density). The phase velocity of the unstable waves also increases with delta. In addition, the growth rate of the instability increases with the beam density and scales as one-third power of the beam density in Cerenkov interaction and square root of beam density in fast cyclotron interaction. Moreover, the dispersion relation of SPWs has been retrieved in the absence of the modulated beam and without dust grains. (C) 2011 American Institute of Physics. [doi:10.1063/1.3591345]