A quantitative test of different magnetic field models using conjunctions between DMSP and geosynchronous orbit

G. D. Reeves, L. A. Weiss, M. F. Thomsen, D. J. McComas

Research output: Chapter in Book/Report/Conference proceedingChapter

10 Scopus citations


We report here on a study which tests the magnetic field line mapping between geosynchronous orbit and the ionosphere. The mapping is determined both observationally and from five magneto spheric magnetic field models. The mapping is tested observationally by comparing electron energy spectra obtained by the Magnetospheric Plasma Analyzer (MPA) at geosynchronous orbit and by the DMSP spacecraft. Because the orbits are nearly perpendicular, in general, the spectra match well for only a few seconds providing a good determination of when DMSP crosses the geosynchronous drift shell. In this way the mapping between geosynchronous orbit and the ionosphere can be determined to better than one degree. We then compare the measured magnetic footpoints of geosynchronous orbit with the footpoints predicted by five magnetospheric field models: Tsyganenko-89, Tsyganenko-87, Tsyganenko-82, Olsen-Pfitzer, and Hilmer-Voigt. Based on a set of over 100 measured magnetic conjunctions we find that, in general, there are significant differences between the mappings predicted by various magnetic field models but that there is no clear "winner" in predicting the observed mapping. We find that the range of magnetic latitudes at which we measure conjunctions is much broader than the range of latitudes which the models can accommodate. This lack of range is common to all magnetic field models tested. Although there are certainly cases where the models are not sufficiently stretched, we find that on average all magnetic field models tested are too stretched. This technique provides an excellent opportunity for testing future magnetic field models and for determining the appropriate parameterizations for those models.

Original languageEnglish (US)
Title of host publicationRadiation Belts
Subtitle of host publicationModels and Standards, 1996
EditorsJ.F. Lemaire, D.N. Baker, D. Heynderickx
PublisherBlackwell Publishing Ltd.
Number of pages6
ISBN (Electronic)9781118664261
ISBN (Print)9780875900797
StatePublished - 1996
Externally publishedYes

Publication series

NameGeophysical Monograph Series
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

All Science Journal Classification (ASJC) codes

  • Geophysics


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