  A mean-density description of spatially-inhomogeneous Bose-condensed gases
based on Bogoliubov's method is introduced. The description assumes only a
large mean atomic density and so remains valid when the mean field collapses
due to phase diffusion. A spread in the number of particles in the condensate
is shown to lead to an anomalous coupling between the condensate and excited
modes. This coupling is due to the dependence of the condensate spatial
wavefunction on particle number and it could, in principle, be used for
reducing particle fluctuations in the condensate.
