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New interplanetary proton fluence modelA new predictive engineering model for the interplanetary fluence of protons with above 10 MeV and above 30 MeV is described. The data set used is a combination of observations made from the earth's surface and from above the atmosphere between 1956 and 1963 and observations made from spacecraft in the vicinity of earth between 1963 and 1985. The data cover a time period three times as long as the period used in earlier models. With the use of this data set the distinction between 'ordinary proton events' and 'anomalously large events' made in earlier work disappears. This permitted the use of statistical analysis methods developed for 'ordinary events' on the entire data set. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. At energies above 30 MeV, the old and new models agree. In contrast to earlier models, the results do not depend critically on the fluence from any one event and are independent of sunspot number. Mission probability curves derived from the fluence distribution are presented.
Document ID
19900060054
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Feynman, Joan
(JPL Pasadena, CA, United States)
Armstrong, T. P.
(Kansas, University Lawrence, United States)
Dao-Gibner, L.
(Syscon Corp. Pasadena, CA, United States)
Silverman, S.
(Boston College Chestnut Hill, MA, United States)
Date Acquired
August 14, 2013
Publication Date
August 1, 1990
Publication Information
Publication: Journal of Spacecraft and Rockets
Volume: 27
ISSN: 0022-4650
Subject Category
Space Radiation
Accession Number
90A47109
Funding Number(s)
CONTRACT_GRANT: NSF ATM-83-05537
Distribution Limits
Public
Copyright
Other

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