Cosmic ray electrons and positrons from supernova explosions of massive
  stars
  We attribute the recently discovered cosmic ray electron and cosmic ray
positron excess components and their cutoffs to the acceleration in the
supernova shock in the polar cap of exploding Wolf Rayet and Red Super Giant
stars. Considering a spherical surface at some radius around such a star, the
magnetic field is radial in the polar cap as opposed to most of 4 pi (the full
solid angle), where the magnetic field is nearly tangential. This difference
yields a flatter spectrum, and also an enhanced positron injection for the
cosmic rays accelerated in the polar cap. This reasoning naturally explains the
observations. Precise spectral measurements will be the test, as this predicts
a simple E^-2 spectrum for the new components in the source, steepened to E^-3
in observations with an E^-4 cutoff.
