Heliosheath Magnetic Field and Plasma Observed by Voyager 2 during 2015 Near Solar Maximum

We discuss magnetic field and plasma observations of the heliosheath made by Voyager 2 (V2) during 2015, when V2 was observing the effects of near-maximum solar activity during solar cycle 24 following the solar minimum in 2009. The average magnetic field strength B was relatively high, 0.126 nT, as expected for solar maximum. A sector structure was observed with nearly equal maximum values of the distribution of directions of daily averages at approximately 90° and 180°, consistent with the Parker spiral magnetic field directions in the heliosheath. This structure indicates that the heliospheric current sheet (HCS) extended to high latitudes above V2 throughout most of 2015. The analysis of one sector boundary confirmed that the HCS was highly inclined (47°) with respect to the equatorial plane. The small-scale increments in B can be described by a -Gaussian distribution with q = 1.60 0.17 for daily averages and q = 1.66 0.03 for hourly averages. The magnetic flux BVRR increased at V2, indicating that there was no significant loss of magnetic energy during 2015. Two merged interaction regions and a global merged interaction region (GMIR) were observed. The flow speed increased as the GMIR moved past V2, indicating that the GMIR was still being compressed by the flow. The GMIR caused a major decrease in the >70 MeV/nuc cosmic-ray intensity. It is likely that the GMIR is causally related to a shock-like disturbance observed by Voyager 1 in the draped interstellar magnetic field beyond the heliopause.