  Micron-sized dust grains have been successfully employed as non-perturbative
probes to measure variations in plasma conditions on small spatial scales, such
as those found in plasma sheaths. The dynamics of the grains can be used to map
the forces due to electric fields present in the sheath, but the particle
charge and electric field are difficult to measure independently. The problem
is further complicated by the ion wake field which develops downstream of the
dust grains in a flowing plasma. Within a sheath, ions are accelerated towards
the charged boundary, and this ion flow creates a positively-charged spatial
region downstream of the dust grain, called the ion wake. The ion wake in turn
modifies the interaction potential between the charged grains. Here we use a
molecular dynamics simulation of ion flow past dust grains to investigate the
interaction between the charged dust particles and ions. The charging and
dynamics of the grains are coupled self-consistently and derived from the
ion-dust interactions, allowing for detailed analysis of the wakefield-mediated
interaction as the structural configuration of the dust grains changes. The
decharging of a dust grain as it moves through the wake of an upstream particle
and the attractive ion wakefield force are mapped for a range of ion flow
speeds.
