Voyager 2 Measurements of Energetic Particles Across the Heliopause

We report on variations in the intensities and angular distributions of energetic (>28 keV) ions and (>22 keV) electrons, and > 213 MeV galactic cosmic ray protons, all measured during the passage of Voyager 2 from the heliosheath into the local interstellar medium. Intensity drops of low-energy heliosheath ions are consistent with the heliopause crossing occurring on or about 5 Nov. (DOY 309) of 2018, at a helioradius of about 119.0 AU, heliographic latitude of -32 deg., and longitude of about 45 deg. from that of Voyager 1, which is near the nose of the heliosphere. We compare these Voyager 2 data with those taken during the Voyager 1 heliopause crossing in Aug. of 2012 at about 121.6 AU. Compared to the Voyager 1 observations made during its heliosheath to interstellar medium transition, those at Voyager 2 show lower levels of interstellar magnetic field and galactic cosmic ray intrusion into the pre-heliopause heliosheath, and longer decay times and markedly different pitch angle distributions of heliosheath suprathermal and anomalous cosmic ray ions that penetrate into the post-heliopause local interstellar medium. A notable similarity is that at both Voyagers the intensities of ~ 50 keV heliosheath electrons began decreasing rapidly roughly an AU prior the heliopause, dropping to background levels before the crossings. Angular distributions of >213 MeV galactic cosmic ray protons measured at Voyager 2 in the heliosheath show a small and varying anisotropy within about 0.4 AU of heliopause, but thereafter in the local interstellar medium distributions are more nearly isotropic.