NOZOMI/ACE Multispacecraft Observations of Solar Energetic Particles

We report multispacecraft measurements of solar energetic particle (SEP) events using NOZOMI and ACE. During July 1998 to April 2002 while NOZOMI was cruising toward Mars, both NOZOMI and ACE observed many SEP events associated with coronal mass ejections (CMEs) and interplanetary shocks originating from different longitudes. The difference in NOZOMI and ACE longitudes varied from 0 to 180 degrees during this period. These observations can reveal the longitudinal extent of CME-driven shocks and the accelerated particle populations. We use proton and electron data extending from ∼40keV to ∼1MeV measured with the EIS instruments on NOZOMI and the ULEIS and EPAM instruments on ACE. Comparisons of the time histories from NOZOMI and ACE as a function of the separation longitude, radius, and flare-locations will be presented.