  We propose a computational framework for the self-consistent dynamics of a
microsphere system driven by a pulsed acoustic field in an ideal fluid. Our
framework combines a molecular dynamics integrator describing the dynamics of
the microsphere system with a time-dependent integral equation solver for the
acoustic field that makes use of fields represented as surface expansions in
spherical harmonic basis functions. The presented approach allows us to
describe the inter-particle interaction induced by the field as well as the
dynamics of trapping in counter-propagating acoustic pulses. The integral
equation formulation leads to equations of motion for the microspheres
describing the effect of non-dissipative drag forces. We show (1) that the
field-induced interactions between the microspheres give rise to effective
dipolar interactions, with effective dipoles defined by their velocities, and
(2) that the dominant effect of an ultrasound pulse through a cloud of
microspheres gives rise mainly to a translation of the system, though we also
observe both expansion and contraction of the cloud determined by the initial
system geometry.
