| Stars, planets, and other bodies in the universe are presumed to have formed from collections of primordial dust: stars from molecular clouds, planets from protoplanetary disks, rings and comets from circumstellar material. A necessary part of this formation is the accumulation of microscopic dust into macroscopic bodies. Generally the strongest force acting on dust particles is gravity or radiation pressure. In many cases, however, the dust coexists with a plasma and becomes charged. For dust grains with a radius smaller than {dollar}sim{dollar}10 microns, the magnitude of the electrostatic force between the grains can be greater than or equal to the magnitude of the gravitational force and can influence the dynamics of particles up to 1 cm in size. These effects play an important role in such phenomena as the coagulation of grains, the formation of Coulomb lattices, and the perturbation of ring particles from Keplerian orbits. This study addresses several of these problems by employing a numerical simulation for the charged dust cloud which allows the consequent coagulation or equilibrium positions of the grains to be explicitly followed. The model allows for a full treatment of rigid body dynamics, including rotation, enabling both cluster trajectories and the orientation of fractal aggregates to be followed. |
