THE STRUCTURE AND EVOLUTION OF INTERPLANETARY SHOCKS AND THE RELEVANCE FOR PARTICLE-ACCELERATION

It is now widely accepted that interplanetary shocks initiated by coronal mass ejections play a dominant role in the generation of the vast majority of large solar energetic particle events. However, our understanding of the details of the acceleration process is far from complete. It is important to better understand the large-scale properties of shocks and how these properties change with distance from the Sun. In this paper I summarize shock and particle observations and. indicate where the problems lie.