Latest Results from ACE on Impulsive Flare Energetic Particles

Joe Mazur

The Aerospace Corporation, 2350 E. El Segundo Blvd.,El Segundo CA 90245

Interplanetary particle events from impulsive solar flares are enriched in Ne-Fe and in the 3He isotope compared to the solar wind; they also show little scattering in the interplanetary medium. The number of impulsive flare particle events observed at 1 AU has significantly increased during the current rise to solar maximum and we have observed their properties with unprecedented detail using instrumentation on board the Advanced Composition Explorer (ACE) spacecraft. Launched into an orbit about L1 in late 1997, ACE has measured the ionic compositions, ionization states, and temporal profiles of dozens of impulsive flares. We will summarize these observations, pointing out the variabilities in the charge states, event profiles, and energy spectra as clues to the acceleration and transport processes.