  We present a simplified model in which we suggest that two important galactic
problems -the magnetic field configuration at large scales and the flat
rotation curve- may be simultaneously explained. A highly convective disc
produces a high turbulent magnetic diffusion in the vertical direction,
stablishing a merging of extragalactic and galactic magnetic fields. The outer
disc may then adquire a magnetic energy gradient very close to the gradient
required to explain the rotation curve, without the hypothesis of galactic dark
matter. Our model predicts symmetries of the galactic field in noticeable
agreement with the large scale structure of our galaxy.
