Solar Energetic Particle Events in the Inner Heliosphere and Deep Space: A Model for Forecasting Proton Fluxes and Anisotropies

ROSES ID: NRA-00-OSS-01      Selection Year: 2001      

Program Element: Independent Investigation: LWS

Principal Investigator: David Lario

Affiliation(s): Applied Physics Laboratory

Summary:

Solar Energetic Particle (SEP) events pose a threat to spacecraft components, materials, and operations. Accurate models for their occurrence, flux profiles, and durations are an important component of space weather. SEP events originate at shocks driven by coronal mass ejections (CMEs) propagating through interplanetary space. Such models must simulate the shock propagation and the injection and transport of shock-accelerated particles. We have developed a model that incorporates these processes. We simulate shock propagation with a magnetohydrodynamic (MHD) time-dependent code, and energetic particle propagation by solving a 1st-order complete transport equation that includes the source of particles accelerated continuously at the moving shock. This model departs from previous particle prediction schemes in that we account for the continuously changing relationship of the observer to the propagating shock. The model reproduces 50 keV-20 MeV SEP proton flux and anisotropy profiles and provides a relationship between the MHD parameters of the shock and the injection rate of shock-accelerated particles. We will use this relationship to create a catalog of simulated SEP events to determine the acceleration efficiency of shocks and to predict the evolution of SEP events. In Year 1 we will build the catalog of SEP events at 1 AU simulated under different heliospheric conditions and configurations. In Year 2 we will extend this catalog to radial distances from 0.3 AU to ~2 AU to provide particle fluences for future NASA missions such as the Inner Heliospheric Sentinels. In Year 3 we will make our results available through the WWW and will study other possibilities for shock modeling and for the injection rate of shock-accelerated particles. Throughout this 3-year project we will build and update a data base of SEP events observed by ACE, IMP-8, Helios-1/2 and compare our calculated fluxes with SEP events in this data base. Our proposed work is central to NASA's Living With a Star program. We will model the evolution of SEP events at Earth and in the inner and outer heliosphere and provide a firm scientific basis for forecasting a key aspect of space weather.

Publications:

Performance Year	Reference	Investigation Type	Actions
1	Lario D.; Decker R. B.; (2002). The energetic storm particle...	Data Analysis
1	Lario D.; Ho G. C.; Decker R. B.; Roelof E. C.; Desai M. I.;...	Data Analysis
2	Lario D.; Simnett G. M.; (2004). Solar Energetic Particle Va...	Data Model Comparison
2	Aran A.; Sanahuja B.; Lario D.; (2005). A first step towards...	Theory and Model Development
2	Aran A.; Sanahuja B.; Lario D.; (2005). Fluxes and fluences ...	Theory and Model Development
2	Lario D.; (2005). Advances in modeling gradual solar energet...	Tools and Analysis Techniques
3	Fry C.; Akasofu S.; Aran A.; Deehr C.; Detman T.; Dryer M.; ...	Data Model Comparison
3	Agueda N.; Lario D.; Roelof E. C.; Sanahuja B.; (2005). Mode...	Data Model Comparison
4	Aran A.; Sanahuja B.; Lario D.; (2006). SOLPENCO: A solar pa...	Data Model Comparison
4	Lario D.; Kallenrode M.-B.; Decker R. B.; Roelof E. C.; Krim...	Data Analysis
4	Aran A.; Lario D.; Sanahuja B.; Marsden R. G.; Dryer M.; Fry...	Data Model Comparison
4	Aran A.; Sanahuja B.; Lario D.; (2008). Comparing proton flu...	Tools and Analysis Techniques

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