Composition measurements above the Southern Solar Polar Region around the solar activity maximum by the Ulysses COSPIN/LET instrument

Abstract

In November 2000, during the second southern polar passage (SPP), the Ulysses spacecraft reached its highest heliographic latitude (80.2°) at a solar radial distance of ~2.27 AU. The first SPP in 1994 took place as the level of solar activity was approaching the minimum between the cycles 22 and 23. The recent high-latitude observations during the second SPP in 2000/2001 correspond to near-maximum activity conditions with a large number of transient phenomena. These heliospheric conditions are reflected in the energetic particle composition data covering the energy range 4-20 MeV/n recorded by the COSPIN/-LET instrument. Most of the particles observed at high heliographic latitudes had their origin in solar energetic particle events. Furthermore, the results suggest coronal mass ejection-driven shock acceleration of coronal material as the source.