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Probabilistic model for low altitude trapped proton fluxes
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Xapsos, M. A. Stassiinopoulos, E. G. Huston, S. L. Barth, J. L. |
| Copyright Year | 2003 |
| Description | A new approach is developed for the assessment of low altitude trapped proton fluxes for future space missions. Low altitude fluxes are dependent on solar activity levels due to the resulting heating and cooling of the upper atmosphere. However, solar activity levels cannot be accurately predicted far enough into the future to accommodate typical spacecraft mission planning. Thus, the approach suggested here is to evaluate the trapped proton flux as a function of confidence level for a given mission time period. This is possible because of a recent advance in trapped proton modeling that uses the solar 10.7 cm radio flux, a measure of solar cycle activity, to calculate trapped proton fluxes as a continuous function of time throughout the solar cycle. This trapped proton model is combined with a new statistical description of the 10.7 cm flux to obtain the probabilistic model for low altitude trapped proton fluxes. Results for proton energies ranging from 1.5 to 81.3 MeV are examined as a function of time throughout solar cycle 22 for various orbits. For altitudes below 1000 km, fluxes are significantly higher and energy spectra are significantly harder than those predicted by the AP8 model. |
| File Size | 617757 |
| Page Count | 8 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20030093744 |
| Archival Resource Key | ark:/13960/t9h46ph6g |
| Language | English |
| Publisher Date | 2003-01-01 |
| Access Restriction | Open |
| Subject Keyword | Solar Physics Time Dependence Spacecraft Orbits International Space Station Space Missions Low Altitude Energy Spectra Probability Theory Proton Energy Mathematical Models Upper Atmosphere Solar Cycles Altitude Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
