  A charge bunch moving in a plasma can excite a variety of linear and
nonlinear waves in the form of trailing wakes, fore-wake shocks and precursor
solitons. These structures can further interact with the background plasma to
create secondary effects that can serve as signatures of the passage of the
charge bunch. Using particle-in-cell simulations we investigate in detail the
dynamics of a plasma system that is being traversed by an energetic charged ion
bunch. Using two different shapes of the charge source, namely, an idealized
one dimensional line source and a two dimensional thin rectangular source we
examine the differences in the nature of the excited wave structures and their
consequent impact on the background plasma. Our simulations reveal interesting
features such as the dependence of the precursor speeds on the total charge of
the ion bunch, local particle trapping, and energization of the trapped ions in
various regions along the traversal path leading to the formation of energetic
ion beam-lets. The collective excitations and the signatures in the ambient
plasma could prove useful in practical applications such as in ion beam heating
of plasmas. They can also help in analysing the trajectories of charged objects
like space debris orbiting in the ionosphere.
