Jostein Riiser Kristiansen: Magnetic fields in the CMB

Large-scale magnetic fields are observed in galaxies and galaxy clusters. The origin
of these fields remains unclear. One possibility is that the fields are amplified
from a primordial seed field generated before recombination. Such fields are for
example predicted by several inflation models. Primordial magnetic fields can be
constrained by observations of the cosmic microwave background radiation (CMB) in
various ways. I will emphasize two approaches: Faraday rotation of the CMB
polarization pattern and temperature anisotropies generated by Alfvén waves.