Imprints of the post recombination dissipation of helical magnetic field
  on the Cosmic Microwave Background Radiation
  Astrophysical magnetic fields decay primarily via two processes namely,
ambipolar diffusion and turbulence. Constraints on the strength and the
spectral index of non-helical magnetic fields have been derived earlier in the
literature through the effect of the above mentioned processes on the Cosmic
Microwave Background (CMB) radiation. A helical component of the magnetic field
is also produced in various models of magnetogenesis, which can explain larger
coherence length magnetic field. In this study, we focus on studying the
effects of post recombination decay of maximally helical magnetic fields
through ambipolar diffusion and decaying magnetic turbulence and the impact of
this decay on CMB. We find that helical magnetic fields lead to changes in the
evolution of baryon temperature and ionization fraction which in turn lead to
modifications in the CMB temperature and polarization anisotropy. These
modifications are different from those arising due to non-helical magnetic
fields with the changes dependent on the strength and the spectral index of the
magnetic field power spectra.
