Dark matter and generation of galactic magnetic fields
  A new scenario for creation of galactic magnetic fields is proposed which is
operative at the cosmological epoch of the galaxy formation, and which relies
on unconventional properties of dark matter. Namely, it requires existence of
feeble but long range interaction between the dark matter particles and
electrons. In particular, millicharged dark matter particles or mirror
particles with the photon kinetic mixing to the usual photon can be considered.
We show that in rotating protogalaxies circular electric currents can be
generated by the interactions of free electrons with dark matter particles in
the halo, while the impact of such interactions on galactic protons is
considerably weaker. The induced currents may be strong enough to create the
observed magnetic fields on the galaxy scales with the help of moderate dynamo
amplification. In addition, the angular momentum transfer from the rotating gas
to dark matter component could change the dark matter profile and formation of
cusps at galactic centers would be inhibited. The global motion of the ionized
gas could produce sufficiently large magnetic fields also in filaments and
galaxy clusters.
