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Magnetospheric field morphology at magnetically quiet times
Author(s) -
Sugiura Masahisa
Publication year - 1973
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs008i011p00921
Subject(s) - dusk , noon , ionosphere , magnetosphere , morning , quiet , ring current , physics , latitude , low latitude , geophysics , middle latitudes , field line , atmospheric sciences , field (mathematics) , night sky , magnetic field , astronomy , mathematics , quantum mechanics , pure mathematics
The magnetospheric morphology is reviewed using the method of the Δ B topology. Typical examples of Δ B profiles along individual passes of OGO‐5 in the morning hours and near noon are given, supplementing similar data presented earlier. These results demonstrate the significance of the equatorial current system in the distortions of the magnetospheric field in its quiet state. A preliminary study of the differences between the observed inclination, I , and I calculated from a reference field, and the corresponding differences in declination, D , shows that Δ I and Δ D are larger than expected from the existing models. The magnitudes of Δ I at low latitudes are larger in the dusk sector than in the dawn sector, suggesting that the equatorial inner magnetosphere is more inflated near dusk than near dawn. The Δ D data show that the bending of the field lines toward the tail is greater in the dusk than in the dawn sector. To account for the large Δ D values at midlatitudes it is suggested that they are caused by field‐aligned currents flowing from the dusk end of the cross‐tail current to the ionosphere and returning to the tail from the ionosphere on the morning side.