  Ambipolar diffusion (AD) is believed to be a crucial process for
redistributing magnetic flux in the dense molecular gas that occurs in regions
of star formation. We carry out numerical simulations of this process in
regions of low ionization using the heavy ion approximation. The simulations
are for regions of strong field (plasma \beta=0.1) and mildly supersonic
turbulence (M=3, corresponding to an Alfven mach number of 0.67). The velocity
power spectrum of the neutral gas changes from an Iroshnikov-Kraichnan spectrum
in the case of ideal MHD to a Burgers spectrum in the case of a shock-dominated
hydrodynamic system. The magnetic power spectrum shows a similar behavior. We
use a 1D radiative transfer code to post-process our simulation results; the
simulated emission from the CS J=2-1 and H13CO+ J=1-0 lines shows that the
effects of AD are observable in principle. Linewidths of ions are observed to
be less than those of neutrals, and we confirm previous suggestions that this
is due to AD. We show that AD is unlikely to affect the Chandrasekhar-Fermi
method for inferring field strengths unless the AD is stronger than generally
observed. Finally, we present the first fully 3D study of the enhancement of AD
by turbulence, finding that AD is accelerated by factor 2-4.5 for non
self-gravitating systems with the level of turbulence we consider.
