Propagation of Energetic Particles to High Heliographic Latitudes

Abstract

The Ulysses spacecraft has now completed its second orbit over the poles of the Sun. Energetic particles associated with CMEs were observed at the highest latitudes over both poles, quite unlike the first polar pass when virtually no CME or CIR accelerated particles were observed at the very highest latitudes. We present observations of solar energetic particle events observed in the energy range $\sim$1 MeV to $\sim$100 MeV made by the COSPIN instrument, when the spacecraft was at high heliographic latitude over the northern pole, above the current sheet, and immersed in high-speed solar-wind flow coming from the northern polar coronal hole. We discuss the rise to maximum, the onset time and the anisotropy of the energetic particles. We find that, unlike the events observed at mid and low latitudes, the particle angular distributions were almost isotropic, but with a net outward flow along the magnetic field lines. We compare these events with other events observed at lower latitudes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html