Future Observations of Cosmic Magnetic Fields with the SKA and its
  Precursors
  The origin of magnetic fields in the Universe is an open problem in
astrophysics and fundamental physics. Polarization observations with the
forthcoming large radio telescopes, especially the Square Kilometre Array
(SKA), will open a new era in the observation of magnetic fields and should
help to understand their origin. Low-frequency radio synchrotron emission, to
be observed with LOFAR, MWA and the SKA, traces low-energy cosmic ray electrons
and allows us to map the structure of weak magnetic fields in the outer regions
and halos of galaxies, in halos and relics of galaxy clusters and in the Milky
Way. Polarization at higher frequencies (1-10 GHz), to be observed with the SKA
and its precursors ASKAP and MeerKAT, will trace magnetic fields in the disks
and central regions of galaxies and in cluster relics in unprecedented detail.
All-sky surveys of Faraday rotation measures towards a dense grid of polarized
background sources with ASKAP (project POSSUM) and the SKA are dedicated to
measure magnetic fields in intervening galaxies, clusters and intergalactic
filaments, and will be used to model the overall structure and strength of
magnetic fields in the Milky Way. "Cosmic Magnetism" is key science for LOFAR,
ASKAP and the SKA.
