Flare-associated energetic particles in the corona and at 1 AU

It is widely believed that the longest lasting and most energetic solar ene rgetic particle events (SEPs) observed in interplanetary space result from acceleration by the bow shocks of coronal mass ejections (CMEs). Using gamm a-ray, X-ray and radio diagnostics of interacting particles and spaceborne and ground-based detection of greater than or equal to 20 MeV protons at 1 AU during two large events (1989 September 29 and October 19), we demonstra te that time-extended acceleration processes in the low and middle corona, far behind the CME, leave their imprints in the proton intensity time profi les in interplanetary space for one to several hours after the onset of the flare: (1) New increases of greater than or equal to 20 MeV proton fluxes at 1 AU can be traced back to episodes of coronal acceleration (2) Increasi ng richness of relativistic protons observed at 1 AU in the course of the S EPs is associated with new coronal particle injection after the impulsive p hase. (3) Particle injection sites enabling a rapid access to the well-conn ected magnetic field line, as required by the SEP time profile, exist in th e middle corona even if the nominal Her flare location is far away. These f indings suggest that contrary to the prevalent view acceleration processes in the low and middle corona supply both interacting and at least part of t he interplanetary particles. The association of the most proton-rich compon ent of the SEPs with delayed low-frequency radio emission is consistent wit h ionization state studies of SEPs, in that both require acceleration in a tenuous plasma. We conclude that the complexity of the corona provides the ingredients for the acceleration of particles and their injection into a la rge range of heliocentric angles. The CME may play the role of a trigger or even contribute to the buildup of magnetic stresses in the corona, but its bow shock is not the main accelerator of the high-energy protons.