  Diffusive shock acceleration (DSA), as an acceleration process for Galactic
electrons at the solar wind termination shock (TS), is investigated with a
comprehensive numerical model which incorporates shock-acceleration, particle
drifts and other major modulation processes in the heliosphere. It is known
from our previous work that the efficiency of DSA depends on the shape of
electron spectra incident on the TS, which in turn depends on the spectral
shape of the very local interstellar spectrum. Modulation processes also
influence the efficiency of DSA. We find that TS accelerated electrons can make
contributions throughout the heliosphere to intensity levels, especially at
lower energies. An interesting result is that increases caused by DSA at the TS
are comparable in magnitude to electron intensity enhancements observed by
Voyager 1 ahead of the TS crossing. These intensity increases are large enough
to account for observed intensity peaks, and thus supports the view that DSA is
involved in their production. Additionally, the energy spectra observed by
Voyager 1 throughout the heliosheath are reproduced satisfactorily, as well as
the PAMELA spectrum at Earth at higher energies. We also find that an increase
in the rigidity dependence of the diffusion coefficients for these low-energy
electrons seems required to reproduce the spectral shape of observed modulated
spectra in the heliosheath at kinetic energy E < ~ 4 MeV. This is different
from intermediate energies where rigidity independent diffusion explains
observations satisfactory.
