  A dense cloud of atoms with randomly changing positions exhibits coherent and
incoherent scattering. We show that an atomic cloud of subwavelength dimensions
can be modeled as a single scatterer where both coherent and incoherent
components of the scattered photons can be fully explained based on effective
multipole moments. This model allows us to arrive at a relation between the
coherent and incoherent components of scattering based on the conservation of
energy. Furthermore, using superposition of four plane waves, we show that one
can selectively excite different multipole moments and thus tailor the
scattering of the atomic cloud to control the cooperative shift, resonance
linewidth, and the radiation pattern. Our approach provides a new insight into
the scattering phenomena in atomic ensembles and opens a pathway towards
controlling scattering for applications such as generation and manipulation of
single-photon states.
