  We believe that the extreme solar modulation of 3-60 MeV Galactic electrons
measured by Voyager in the heliosheath and the interpretation of this new data
in terms of the rigidity dependence of the diffusion coefficient at low
rigidities presented in this paper represents a major step in understanding
diffusion theory as it applies to energetic particles. This description uses
electron spectra measured at 5 different epochs and distances within the
heliosheath. The diffusion dependence needed to explain the remarkable solar
modulation effects observed for both electrons and higher rigidity protons as
one progresses from the heliopause inward by ~25 AU to the termination shock
really has two distinct rigidity regimes. Above a rigidity ~Pc the diffusion
coefficient has a dependence ~beta P, the modulation is ~P and its magnitude
increases linearly with radius in AU according to the integral of dr/K. This
integral defines a potential, beta, called the modulation potential, thus
explaining the proton variations. At rigidities <Pc, the diffusion coefficient
is ~beta and independent of rigidity. The modulation is also independent of
rigidity but its magnitude depends on the modulation potential, thus explaining
the electron modulation. One needs both electron and proton observations,
together, to recognize the physical description of the solar modulation
process. For the first time we have been able, using proton data at high
rigidities and electron data at low rigidities, to put together a picture of
the high and low rigidity diffusion coefficients and how they affect energetic
particles in an astrophysical scale environment.
