Cosmological Simulations using GCMHD+
  Radio observations of galaxy clusters show that the intra cluster medium is
permeated by \mu G magnetic fields. The origin and evolution of these
cosmological magnetic fields is currently not well understood and so their
impact on the dynamics of structure formation is not known. Numerical
simulations are required to gain a greater understanding and produce
predictions for the next generation of radio telescopes. We present the
galactic chemodynamics smoothed particle magnetohydrodynamic (SPMHD) code
(GCMHD+), which is an MHD implementation for the cosmological smoothed particle
hydrodynamic code GCD+. The results of 1, 2 and 3 dimensional tests are
presented and the performance of the code is shown relative to the ATHENA grid
code. GCMHD+ shows good agreement with the reference solutions produced by
ATHENA. The code is then used to simulate the formation of a galaxy cluster
with a simple primordial magnetic field embedded in the gas. A homogeneous seed
field of 10^-11 G is amplified by a factor of 10^3 during the formation of the
cluster. The results show good agreement with the profiles found in other
magnetic cluster simulations of similar resolution.
