Chee K. Ng1,2, Donald V. Reames1, Allan J. Tylka3

1 Code661, Lab for High Energy Astrophysics, NASA/Goddard Space Flight Center
2 Department of Astronomy, University of Maryland, College Park
3 E O Hulburt Center for Space Research, Code 7654, Naval Research Laboratory

Classical quasilinear theory of wave-particle interaction implies significant energetic proton-driven Alfvén wave growth in the inner heliosphere for gradual SEP events with peak intensity greater than ~ 200 protons (cm² s sr MeV)^-1. We show how this is implied by the energetic proton fluxes predicted by classical models of SEP transport. The energy density of the amplified waves is only a few percent of that in the energetic protons, yet these waves have a profound effect on the transport of energetic ions. Observational evidence of wave growth has been found in the time variations of SEP elemental abundances, which are in agreement with the prediction of a simple time-dependent model of ion transport coupled to SEP amplified waves. The important question to be addressed now is how these amplified waves are transported and dissipated.