SOLPRO Model 1975


Author: E. G. Stassinopoulos
NASA/GSFC, Code 930
Greenbelt, Maryland 20771

Parameter: Solar proton fluences (10 MeV to 100 MeV)

Brief Description:
SOLPRO is the computer version of the interplanetary proton fluence model developed by King (1974) and Stassinopoulos and King (1974). The model is based on the most continuous set of satellite data available at the time covering the period of enhanced solar activity during solar cycle 20 (1964-1972). Because of its size, the August 1972 event produced a fluence more than a factor of 10 larger than any other event in cycle 20. For that reason, King (1974) treats this event separately and calls it an anomalously large (AL) event. The FORTRAN subroutine SOLPRO calculates the interplanetary solar proton fluences (at 1 A.U. [Astronomical Unit] = Earth-Sun distance) as a function of mission duration (in months), energy threshold (in MeV), and confidence level (in percent). For a given combination of input parameters, the code determines whether an anomalously large (AL) event needs to be considered and, if so, how many. For missions whose trajectories involve significant time away from a heliocentric distance of 1 A.U., a helioradial dependence of event fluences must be considered (King, 1974). Similarly, for missions whose trajectories involve partial magnetospheric shielding, the fractional exposure factor has to be determined (Stassinopoulos and King, 1974). The model strongly depends on the fluence of the 1972 AL event. This has led to over-predictions for cycle 21. Cycle 21 did not show a major event.

Availability: (1) Retrievable from CCMC's anonymous FTP site in directory /solpro. <

References:
J. H. King, Solar Proton Fluences for 1977-1983 Space Missions, J. Spacecraft Rockets 11, 401, 1974. (B18663)

E. G. Stassinopoulos and J. H. King, Empirical Solar Proton Model for Orbiting Spacecraft Applications, IEEE Trans. Aerospace Electronic Systems 10, 4, 1974. (B17234)

J. H. King and E. G. Stassinopoulos, Energetic Solar Protons vs. Terrestrially Trapped Proton Fluxes for the Active Years 1977-1983, J. Spacecraft Rockets 12, 122, 1975. (B20337)

E. G. Stassinopoulos, SOLPRO: A Computer Code to Calculate Probabilistic Energetic Solar Proton Fluences, NSSDC 75-11, Greenbelt, Maryland, 1975. (B23274)


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