Observations of the solar corona with ulysses: Expectations above the polar regions

Abstract

During its prime mission phase, the Ulysses space probe will fly above both solar poles, providing an unprecedented opportunity to study the high latitude regions of the solar corona. The timing of the polar passes (mid-1994 and mid-1995) coincides with solar minimum, corresponding to a coronal configuration consisting of well-developed polar coronal holes and a near-equatorial heliospheric current sheet. The nine sets of instruments that make up the Ulysses scientific payload are expected to return unique data concerning the high latitude solar wind and interplanetary magnetic field, as well as the solar energetic particles that populate these regions. We present a review of some of these expectations, illustrated by results obtained in 1991 during the in-ecliptic phase of the Ulysses mission.