National Aeronautics and Space Administration

Living With A Star

Targeted Research and Technology

Modeling the Long-Term Variations of Energetic Trapped Protons

ROSES ID: NRA-02-OSS-01      Selection Year: 2003      

Program Element: Independent Investigation: LWS

Principal Investigator: Stuart L. Huston

Affiliation(s): Boeing Phantom Works

Project Member(s):
Xapsos, Michael Anthony COI NASA/GSFC
Heynderickx, D. COI BIRA
Huston, Stuart Authorizing Official


We propose to develop methods to model the secular, seasonal, and solar cycle variations of the energetic protons in the Inner Zone. The effort will involve merging data from the low altitude POES and SAMPEX spacecraft as well as from CRRES to develop a data base of proton data covering more than two solar cycles and energies from 1 to 500 MeV. Each of these spacecraft has unique advantages and disadvantages. CRRES provides good energy resolution and covers essentially the entire radiation belt region, but the data extend only up to 100 MeV. SAMPEX provides data out to 500 MeV, but only at low altitude. POES has relatively poor energy resolution, but provides data covering more than two solar cycles. The spacecraft data will be augmented with simulations performed using the Salammb code in order to extend the spatial region of validity of the low altitude SAMPEX and POES data. In addition, we will develop a statistical model which for the first time will allow spacecraft designers to predict proton fluxes as a function of confidence level for any time period of interest. This trapped proton model will allow the design of more capable and robust spacecraft, and will also provide valuable insight into the source, transport, and loss mechanisms operating in the radiation belts. This project is a collaboration of researchers from the U.S. and Europe and thus provides the maximum return for NASA funding.


Performance YearReferenceInvestigation TypeActions
1Huston, Stuart Huston Asso - Modeling the Long-Term Variatio...
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1Fung, S. F.; Bell, E. V.; Tan, L. C.; Candey, R. ...
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Performance YearReferenceActions
1Fung, S. F.; Shao, X.; Bell, E. V.; Tan, L. C.; M...

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