Properties of high heliolatitude solar energetic particle events

Several solar energetic particle (SEP) events were detected by Ulysses at high heliographic latitudes during the recent solar maximum polar passes. We address the question of whether the characteristics of high latitude SEP events are systematically different from those of in-ecliptic ones. We consider time intensity profiles of nine large events measured by the COSPIN suite of instruments on Ulysses and in the ecliptic by Wind/3DP and SOHO/COSTEP. We perform an analysis of onsets in several energy channels, which yields values of the apparent time of particle release from the solar atmosphere, and path length travelled by the particles. We also measure the time to maximum in the intensity profiles. We find large delays in particle onsets at high latitudes. The magnitude of the delay increases with the difference between latitude of the spacecraft and latitude of the associated flare. This suggests that energetic particles reach the high latitude magnetic field lines by cross field scattering.