  We investigate the behavior of the magnetic Prandtl number (ratio of
microscopic viscosity to resistivity) for accretion sources. Generally this
number is very small in standard accretion disk models, but can become larger
than unity within $\sim 50$ Schwarzschild radii of the central mass. Recent
numerical investigations suggest a marked dependence of the level of MHD
turbulence on the value of the Prandtl number. Hence, black hole and neutron
star accretors, i.e. compact X-ray sources, are affected. The astrophysical
consequences of this could be significant, including a possible route to
understanding the mysterious state changes that have long characterized these
sources.
