Donald V. Reames

Laboratory for High Energy Astrophysics, NASA/GSFC, Greenbelt, MD 20771, USA

In recent years we have learned much about the role of wave-particle interactions in the acceleration and transport of solar energetic particles (SEPs) in the large 'gradual' events.  Perhaps these events have been easier to study because the large spatial and temporal extent of the CME-driven shock waves, where acceleration occurs, even allows multiple observations in situ.  Compact flares, where wave energy may predominate, should be the ideal sites for the study of wave-particle physics.  Yet there are nagging questions about the magnetic geometry, the relation between ions that escape and those that interact, and the relative roles of cascading Alfvén waves and the EMIC waves required to enhance  ³He.  There are also questions about the relative timing of ion and electron acceleration and of heating; these relate to the variation of ionization states before and during acceleration and during transport out of the corona.  Gradual and impulsive SEP events involve many of the same physical processes, though in much different degrees; what we learn from one may help us understand the other.