  With the cosmic ray observations made by the Voyager 1 spacecraft outside the
dominant modulating influence of the heliosphere, the comparison of computed
galactic spectra with experimental data at lower energies is finally possible.
Spectra for specifically protons, Helium and Carbon nuclei, computed by
galactic propagation models, can now be compared with observations at low
energies from Voyager 1 and at high energies from the PAMELA space detector at
Earth. We set out to reproduce the Voyager 1 observations in the energy range
of 6 MeV/nuc to 60 MeV/nuc, and the PAMELA spectrum above 50 GeV/nuc, using the
GALPROP code, similarly to our previous study for Voyager 1 electrons. By
varying the galactic diffusion parameters in the GALPROP plain diffusion model,
specifically the rigidity dependence of spatial diffusion, and then including
reacceleration, we compute spectra simultaneously for galactic protons, Helium
and Carbon.We present new local interstellar spectra, with expressions for the
energy range of 3 MeV/nuc to 100 GeV/nuc, which should be of value for solar
modulation modeling.
