  Magnetic fields play an important role in almost all astrophysical phenomena
including star formation. But due to the difficulty in analytic modeling and
observation, magnetic fields are still poorly studied and numerical simulation
has become a major tool. We have implemented a cosmological
magnetohydrodynamics package for Enzo which is an AMR hydrodynamics code
designed to simulate structure formation. We use the TVD solver developed by S.
Li as the base solver. In addition, we employ the constrained transport(CT)
algorithm as described by D. Balsara. For interpolation magnetic fields to fine
grids we used a divergence free quadratic reconstruction, also described by
Balsara. We present results from several test problems including MHD caustics,
MHD pancake and galaxy cluster formation with magnetic fields. We also discuss
possible applications of our AMR MHD code to first star research.
