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Some initial ISEE‐1 results on the ring current composition and dynamics during the magnetic storm of December 11, 1977
Author(s) -
Lennartsson W.,
Shelley E. G.,
Sharp R. D.,
Johnson R. G.,
Balsiger H.
Publication year - 1979
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl006i006p00483
Subject(s) - magnetosphere , physics , ring current , geomagnetic storm , ion , solar wind , plasma sheet , geophysics , noon , storm , dusk , atmospheric sciences , astrophysics , plasma , astronomy , meteorology , nuclear physics , quantum mechanics
The ISEE‐1 spacecraft carries a mass spectrometer for ions with E/Q ≤ 17 keV/e. On December 11, 1977, it traversed the equatorial magnetosphere in the prenoon and dawn sectors during the early recovery phase of a magnetic storm with peak D ST =−125γ. Along the dayside (inbound) leg O + was comparable to or exceeded H + in number density in the energy range 0.1 keV ≤ E ≤ 17 keV. The velocity distribution of O + showed a characteristic dispersion, consistent with the ions being transported to the dayside from the dusk to midnight sector. The high‐energy slope of the H + and O + distribution functions showed different radial dependence, with the slope of H + being consistent with a harder component carrying most of the energy density. Along the nightside (outbound) leg the O + density was very low outside of 5 R E , and most of the number denisty was due to the hard H + component.