Ionization from Cosmic Strings at Cosmic Dawn
  Cosmic strings produce charged particles which, by emitting electromagnetic
radiation, partially ionize neutral hydrogen during the dark ages. Corrections
to the ionization fraction of neutral hydrogen induced by cosmic strings could
lead to new observational effects and/or new constraints on the string tension
around $G\mu \sim 10^{-16} - 10^{-22}$ for values of the primordial magnetic
field in the range $B_0 \sim 10^{-11}-10^{-9}$ Gauss.
