  We consider 6 types of scaling limits for the Wigner-Moyal equation of the
parabolic waves in random media, the limiting cases of which include the
radiative transfer limit, the diffusion limit and the white-noise limit. We
show under fairly general assumptions on the random refractive index field that
sufficient amount of medium diversity (thus excluding the white-noise limit)
leads to statistical stability or self-averaging in the sense that the limiting
law is deterministic and is governed by various transport equations depending
on the specific scaling involved. We obtain 6 different radiative transfer
equations as limits.
