FIRST ENERGETIC PARTICLE EVENTS OBSERVED BY THE ERNE INSTRUMENT

he energetic particle instrument ERNE on board SOHO started its observ ations on Decem ber 15, 1995. The low-energy sensor of ERNE, LED, is c apable of measuring particles in the energy range from 1 to 10 MeV nuc l(-1). From the beginning of the year 1996 until May 22, 1996, LED-obs ervations included four energetic particle events above threshold inte nsities. An energetic particle event caused by a corotating interactio n region that accelerated protons upto similar to 10 MeV, was observed during January 20-25. Another similar particle event occured on May 6 -12. The events were separated by four solar rotation periods. They ha d similar time profiles, but thr one in May had had a harder spectrum and a lower intensity level. The He-4-to-proton ratios were in accorda nce with the solar wind value. Energetic particles observed during Apr il 22-23 and May 14-17 were accelerated at the Sun. The first one was apparently an outcome from an active region observed on the west limb by telescopes onboard SOHO. Protons were detected at energies from 1 t o similar to 10 MeV. For this event, the 4He-to-proton ratio in the ra nge 1.5-5 MeV nucl(-1) was similar to 3%. No He-3 ions were detected. The period of May 14-5 was, in contrast, extremely He-3-rich: it had a He-3 to-proton ratio of 1.5 +/- 0.6 and a He-3-to-He-4 ratio as high as Ns. The period of May 14-17 comprised at least three individual, on e-day-long events. The first two events were He-3-rich, while the last one seemed to have a normal composition.