Solar Energetic Particle Events in the Rising Phase of Solar Cycle 23: Observations at 1 and 5 AU

Abstract

We present energetic particle observations by the Ulysses and WIND spacecraft during the years 1997-1998. This period corresponds to the onset of the new solar cycle (23) when the increasing level of solar activity started to produce solar energetic proton (SEP) events. Several large and long-lasting SEP events were observed by both spacecraft during episodes of intense solar activity, even when their heliolongitudinal and heliocentric separation was large. We focus the study on the SEP events observed by WIND and Ulysses during November 1998. We suggest an interpretation of these events in terms of the activity occurring at the Sun and the heliospheric location of both spacecraft.