ABSTRACT
The dynamics of charged dust grains in space attracted the main stream of interest of space physicists about 20 years ago, when Voyager 1 and 2 passed Saturn and sent back pictures of mysterious dark spokes sweeping around the B ring (Smith et al 1981, 1982). It was then independently proposed by Hill and Mendis (1981a) and Goertz and Morfill (1983) that the spokes might be charged dust and sculptured by electrostatic forces. The dynamical patterns of charged dust particles in interplanetary space observed by Voyager 1 and 2 also seem to account for the combined effects of electromagnetic and gravitational forces acting on the dust particles. On the other hand, in laboratory plasmas, dust particles, which are subjected to various forces, often accumulate near the plasma boundaries (walls) and cause contamination to substrates and wafers (Selwyn 1993). It is, therefore, crucial to understand the behaviour of macroscopic particles under the action of various forces (such as gravitational force, electric force, ion drag force, neutral drag force, thermophoretic force, etc) in order to control the dust transport. Thus, in this chapter, we confine ourselves to the study of different forces acting on charged dust particles and their dynamics in both space and laboratory dusty plasmas. The forces that are relevant to dust grain crystallization are discussed in chapter 8.
