  Some spontaneously broken gauge theories with unbroken non-Abelian gauge
groups contain massless magnetic monopoles that are realized classically as
clouds of non-Abelian field surrounding one or more massive monopoles. We use
moduli space methods to investigate the properties of these massless monopole
clouds. We show that the natural metric on the Nahm data for a class of
SU(2M+2) solutions with 2M massive and M(2M-1) massless monopoles can be
obtained from that for a simpler class of SU(M+1) solutions. For the M=1 case,
we show that the Nahm data metric is isomorphic to the metric for the moduli of
the BPS solutions, thus verifying a previously conjectured result. For M=2 we
use our results and the moduli space approximation to obtain an effective
Lagrangian for an axially symmetric class of solutions. Using this Lagrangian,
we study the interactions between the two types of clouds that appear. We show
that, although the static spacetime field configurations suggest that the
clouds might be rather diffuse, in scattering processes they behave as if they
were relatively thin hard shells.
