Excitation of ion cyclotron waves by a spiraling ion beam in a magnetized dusty plasma cylinder

Abstract

A spiraling ion beam propagating through a magnetized dusty plasma cylinder drives electrostatic ion cyclotron waves to instability via cyclotron interaction. Numerical calculations of the growth rate and unstable mode frequencies have been carried out for the typical parameters of dusty plasma experiments in the two limits, namely, long parallel wavelength and short parallel wavelength. It is found that as the density ratio of negatively charged dust grains to electrons increases, the unstable mode frequency and the growth rate of the instability of the ion cyclotron waves increase in both the limits. The growth rate of the instability increases by a factor of ∼2.5 when the density ratio of negatively charged dust grains changes from 1.0 to 4.0 in the limit of short parallel wavelengths. Moreover, the growth rate increases with the density ratio of negatively charged dust at higher values in the present case in the limit of long parallel wavelengths. The growth rate of the unstable mode has the largest value for the modes whose eigenfunctions peak at the location of the beam. The growth rate of the instability scales as the one-third power of the beam current in both limits.