This team proposes a three-year research program to use state-of-the-art composition measurements from Advanced Composition Explorer (ACE) and Wind (and possibly STEREO (Solar Terrestrial Relations Observatory) near 1 AU, Ulysses at high-and-low solar latitudes, and Cassini en route to Saturn) to model the temporal and spatial evolution of the suprathermal ion population in the 3D-heliosphere between ~1 and 10 AU. The proposers plan to develop a theoretical framework for understanding the main causes of the variability of the suprathermal tail and model its dynamical properties through the inner heliosphere. They also plan to investigate the effects of the inherent variability of the suprathermal tail on coronal mass ejection (CME) shock-associated ion populations in the heliosphere. The resultant numerical model will provide a realistic prescription for the dynamical properties of the suprathermal seed population through the inner heliosphere and could ultimately be utilized by future end-to-end global models of CME initiation, evolution, propagation, and solar energetic particle (SEP) acceleration. The proposed work also will probe, for the first time, the spatial and temporal dependence of stochastic acceleration mechanisms that produce suprathermal ions in the inner heliosphere.
This will provide a sound basis for enabling broader theoretical investigations involving the production of suprathermal ions at a variety of astrophysical sites, including the termination shock, solar flares, and supernova shocks. This effort could also aid the development of a global space weather monitoring system to accurately predict radiation levels during CME/SEP events. Several graduate and undergraduate students will be partially supported through this project. The proposers have established a strong record of mentoring students.
