Intensity Variations of Suprathermal Heliosheath Ions Measured at Voyagers 1 and 2

Both Voyagers 1 (V1) and 2 (V2) are in the inner heliosheath (HSH) behind the termination shock (TS). V1 crossed the TS during day 351 of 2004 and V2 crossed during days 242-245 of 2007. From 2004/351 to 2009/230, V1 moved in helioradius over 94-111 AU at heliographic latitude N34°, and from 2007/242 to 2009/230, V2 moved over 84-90 AU at S28°. Throughout V2's two-year HSH cruise, the V2/LECP instrument has measured quasi-recurrent (15-35 day) variations in the intensities of suprathermal ions (30 keV-few MeV in 8 energy intervals). Comparable variations are not been seen in the V1/LECP ion data. To help understand these HSH ion data in terms of what was occurring on the sun a year or so earlier, we examined synoptic polar coronal hole maps from the Global Oscillation Network Group (GONG). Our focus was on possible relations between HSH ion intensity variations and equatorward extensions of polar coronal holes that produce stream interaction regions in the solar wind, which can propagate into the outer heliosphere and into the TS/HSH. The results are promising, not only in helping explain the presence of the quasi-periodic intensity variations at V2 and the lack thereof at V1, but also in enabling us to predict what V1 and V2 are likely to see at their respective latitudes in the future. Another aspect of the V2 data that we will report on is the possible presence, albeit intermittent, of another ion species besides protons in the ~30-200 keV total energy range. Specifically, the angular distributions of the lower energy channels show convective signatures that indicate a mixture protons and helium ions. We are using the HSH plasma flow velocity measured by V2/PLS and modeling the LECP response to confirm these preliminary results and provide estimates of low-energy HSH helium intensities.