  The range of microphysical and global dynamical timescales in the central
regions of Active Galactic Nuclei (AGN) is sufficiently wide to permit the
existence of multiphase structure. In particular, very dense, cool clouds can
coexist with a hot, magnetically-dominated medium and can thereby efficiently
reprocess the continuum radiation generated in this primary source region. The
strong dynamical forces in this central magnetosphere can give rise to
extremely small clouds. Microphysical processes then determine whether such
clouds can indeed survive, in spite of their extremely contrasting properties
relative to the surrounding environment, for long enough to produce potentially
observable thermal reprocessing signatures. We examine specific physical
constraints on the thicknesses of such reprocessing clouds. Our results are
plotted to show the range of conditions that is representative of the central
regions of AGN. We find a parameter subspace in the extreme high density regime
for which the effects of microphysical diffusion processes can be overcome and
for which cool gas can maintain pressure equilibrium with the ambient
magnetosphere.
