The Interactions of Energetic Particles with the Solar Wind - A Theoretical Study

University Of New Hampshire, Durham NH

Investigators

Abstract

The investigators will work toward a quantitative understanding of the energetic particle structure of the heliosphere and the fundamental processes that govern that structure. The main effort concentrates on theoretical studies of the interactions of energetic particles with the solar wind. The studies will be broad-based and include solar energetic particles, galactic cosmic rays, interstellar pickup ions, shock-accelerated particles such as the corotating ion events, and the solar wind itself. The investigations will include both the global spatial and temporal distributions of the energetic particles, and the microprocesses governing their interactions with the ambient plasma, including wave excitation by the energetic particles. Analytical methods will be emphasized where possible. The studies will also emphasize comparisons between the theoretical predictions and ground-based and spacecraft observations, including specifically those by ACE, SOHO, Cluster, Wind, Ulysses and Voyager. Specific topics of research include an analytical theory for the acceleration and transport of solar energetic particles at an evolving coronal/interplanetary shock including proton-excited waves and magnetic focusing, which propels ions from the turbulent sheath adjacent to the shock into interplanetary space. The investigators will construct an improved theory of ion acceleration at corotating interaction regions in the solar wind including injection mechanisms, a sheath of proton-excited waves, and azimuth asymmetry of the accelerated interstellar pickup ions. They will also investigate of the evolution of the proton and minor ion distribution functions in the solar wind due to gravity, the ambipolar electric field, magnetic focusing and scattering by ion-cyclotron waves.