  We calculate the field eigenmodes of the superradiant emission from an
ensemble of $N$ two-level atoms. While numerical techniques are effective due
to the symmetry of the problem, we develop also an analytical method to
approximates the modes in the limit of a large number of emitters. We find that
Dicke superradiant emission is restricted to a small number of modes, with a
little over 90\% of the photons emitted in a single dominant mode.
