A Search for Interplanetary Energetic Particle Events from Solar Posteruptive Arcades

Abstract

While the E > 10 MeV ions observed in gradual solar energetic particle (SEP) events in space are attributed to acceleration at shocks driven by coronal mass ejections (CMEs), it has been suggested that such SEPs may also be produced in the magnetic reconnection of coronal arcades following CMEs. The arcade SEPs could escape the corona along open field lines and provide additional contributions to observed gradual SEP events. We searched for SEP events associated with large, bright solar soft X-ray arcades and intense metric noise storms in the western hemisphere, which should be favorable for the production of arcade SEP events observed at 1 AU. Five arcades/storms were possibly or definitely associated with IMP-8 24-28 MeV proton increases, but the latter appear to be shock accelerated. We also found 30 arcades (14 in active regions and 16 outside active regions) with no detectable SEP increases, suggesting that those arcades were not sources of escaping SEPs. This result provides evidence against the possibility of coronal arcade contributions to gradual SEP events.