  We simulate the evolution of an initially weak magnetic field in forced
turbulence for a range of Prandtl numbers. The field grows exponentially with
the Kulsrud-Anderson $k^{3/2}$ spectrum until the magnetic energy approaches
the viscous-scale kinetic energy, where the magnetic forces then backreact on
the velocity. Further growth proceeds more slowly until a saturated state is
reached where the magnetic and kinetic energies are equal, and where the
magnetic energy exists primarily at the resistive scale. We discuss the
structure of this turbulence and the extrapolation of the results to
astrophysically-large Prandtl numbers.
