VizieR Online Data Catalog: H through Ni intensities in LISM from Voyager 1 (Cummings+, 2016)

Since 2012 August Voyager 1 has been observing the local interstellar energy spectra of Galactic cosmic-ray nuclei down to 3MeV/nuc and electrons down to 2.7MeV. The H and He spectra have the same energy dependence between 3 and 346MeV/nuc, with a broad maximum in the 10-50MeV/nuc range and a H/He ratio of 12.2+/-0.9. The peak H intensity is ~15 times that observed at 1AU, and the observed local interstellar gradient of 3-346MeV H is -0.009+/-0.055%/AU, consistent with models having no local interstellar gradient. The energy spectrum of electrons (e^-+e⁺) with 2.7-74MeV is consistent with E^-1.30+/-0.05 and exceeds the H intensity at energies below ~50MeV. Propagation model fits to the observed spectra indicate that the energy density of cosmic-ray nuclei with >3MeV/nuc and electrons with >3MeV is 0.83-1.02eV/cm³ and the ionization rate of atomic H is in the range of 1.51-1.64x10^-17s^-1. This rate is a factor >10 lower than the ionization rate in diffuse interstellar clouds, suggesting significant spatial inhomogeneity in low-energy cosmic rays or the presence of a suprathermal tail on the energy spectrum at much lower energies. The propagation model fits also provide improved estimates of the elemental abundances in the source of Galactic cosmic rays.

(4 data files).