Electrostatic Modes

Abstract

Many of the papers about waves in dusty plasmas are dealing with electrostatic modes, so it is natural to start our overview of dusty plasma with these, and leave the electromagnetic waves for the next chapter. Electrostatic waves are easily generated, for example, when a perturbation creates a charge imbalance in a fluid element that was originally charge neutral. Such an imbalance will accelerate electrons (and also ions and other charged particles) in the neighbourhood of the charged fluid element, resulting in charges oscillating back and forth, essentially involving the electric field and hence called electrostatic. The oscillating magnetic field is either absent or can be neglected. In that case, Faraday’s law (4.52) shows that the electric field E is parallel to the direction of the wave vector k.