Hydrogen recombination in the early Universe in the presence of a
  magnetic field
  Hydrogen recombination in the early Universe in the presence of a magnetic
field is studied. An equation for the temperature of recombination in the
presence of a magnetic field is derived. Limiting cases of weak and strong
fields are considered. It is demonstrated that there exists a critical magnetic
field, above which the system stays in the phase of atomic hydrogen for all
temperatures. The relative shift of the temperature of recombination in the
presence of a magnetic field is estimated and it is demonstrated that this
shift is small.
