Composition Measurements over the Solar Poles Close to Solar Maximum - Ulysses COSPIN/LET Observations

摘要

We present energetic particle composition measurements acquired on board the Ulysses spacecraft in 2000 and 2001 during its recent south and north polar passages. In an earlier study using data only from the south polar pass (Hofer et al., 2002), we found that the high-latitude composition data reflected the generally high level of solar activity present during that period. The observed particle populations during the south and north polar passages comprised predominantly of solar energetic particles (SEP) accelerated in association with CMEs, rather than particles related to SIR or CIRs. In this work, we compare the energetic particle composition signatures in the two helio-hemispheres, and find that the latest data from the north polar pass show the same transient-dominated signature as in the south.