Temporal evolution of superradiance in a small sphere

We discuss the problem of calculating the superradiant behavior in samples small compared to a radiation wavelength. Difficulties associated with the analysis of Dicke are considered in the framework of quantum electrodynamics and equivalently from a classical point of view. The evolution of superradiance in a small sphere is followed numerically with attention to spatial variation of the Bloch dipole density. Coherence is maintained except in the region (kR)^-1|cosθ|2 which is at the Bloch equator, where it suddenly disappears. Away from the equator, the spatial variations of dipole density oscillate with amplitude ~(kR)²sinθ and frequency ~(kR)^-3|cosθ|. All these results agree with the predictions of a theoretical discussion previously published.