  We consider fast magnetic reconnection that takes place within turbulent
magnetic flux and show that the process results in diffusion of magnetic fields
and matter, which we term reconnection diffusion. The process of reconnection
diffusion is based on the model of 3D reconnection of weakly turbulent magnetic
fields and is applicable to both fully ionized and partially ionized gas. The
rate of reconnection diffusion does not depend on the level of ionization and
therefore the usually employed ambipolar diffusion idea gets irrelevant for
magnetic field transport in turbulent fluids. We claim that the reconnection
diffusion process is a manifestation of the violation of flux conservation in
highly conducting turbulent fluids. We discuss the consequences of reconnection
diffusion for star formation and stress. We show that reconnection diffusion on
large scales is independent of small scale magnetic field dynamics of magnetic
fields. We conclude that numerical simulations correctly represents the
diffusion of actual astrophysical magnetic fields in flows with substantially
larger Lundquist numbers if these simulated regions regions are turbulent.
