Relationship between Ulysses plasma observations and solar observations during the Whole Sun Month campaign

In this report, we summarize measurements made by the plasma experiment on the Ulysses spacecraft during the period designated as “Whole Sun Month” (WSM, August 10 to September 8, 1996). This interval coincided with the return of solar wind variability at Ulysses. Ulysses was located at ∼ 28°N heliographic latitude, at a heliocentric distance of 4.25 AU, and on the opposite side of the Sun from Earth. In particular, we explore the evolution of the solar wind between the Sun and Ulysses for several rotations surrounding WSM. Specifically, we map Ulysses measurements back toward the Sun by applying a two‐dimensional inverse MHD algorithm. This approach is compared with the commonly used constant speed (or ballistic) approximation. We find that the MHD mapping technique produces substantially better results when compared with solar observations. Both the Ulysses MHD‐mapped results and the solar observations are consistent with a picture of a modestly tilted streamer belt (< 10°) that was deformed northward by an active region at 240° –; 270° longitude.