  The large intensity of greater than 10 GeV positrons which apparently come
from sources outside the Earth-Sun system observed recently by many spacecraft
(PAMELA, FERMI, AMS2) is still a mystery with broad implications. In our
attempts to solve this mystery we have first tried to define reasonable limits
to the positrons produced in our own galaxy by nuclear interactions of cosmic
rays. This is best done by using the secondary B/C ratio produced by these same
cosmic rays in order to define the amount of matter traversed by galactic
cosmic ray nuclei. Using new values of the B/C ratio together with earlier
calculations of positron production by Moskalenko and Strong, 1998, we find
that at 10 GeV this galactic production is from 70% to almost 100% of the
positrons observed by the above experiments. At 100 GeV these fractions are
still from 20 to 33% of the positrons observed. The resulting excess positron
spectrum above this normal galactic background is found to have an exponent
-2.75, possibly flattening at lower energies. If these positrons are coming to
us from a uniform source distribution in and beyond the disk of the galaxy with
a source spectrum that is E-2.0, a spectral steepening caused by synchrotron
and inverse Compton losses, which are largest near the galactic plane, will
produce a spectrum E-2.75 at the Earth. This is similar to the excess spectrum
we find. The excess positron spectrum E-2.75 that we obtain is also very
similar to the positron spectrum produced by galactic protons in the Earths
atmosphere and in the spacecraft itself which also has a spectrum E-2.75. This
results in a background for all the above experiments. The assumption is that
this type of background is removed by the stringent criteria that are imposed
on each event. This calculation needs to be reconsidered before the
implications of these important positron results can be fully evaluated.
