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Tailward energetic ion streams observed at ∼100 R E by GEOTAIL‐EPIC associated with geomagnetic activity intensification
Author(s) -
Jacquey C.,
Williams D. J.,
McEntire R. W.,
Lui A. T. Y.,
Angelopoulos V.,
Christon S. P.,
Kokubun S.,
Yamamoto T.,
Reeves G. D.,
Belian R. D.
Publication year - 1994
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 - 10.1029/94gl01606
Subject(s) - electrojet , substorm , physics , earth's magnetic field , solar wind , flux (metallurgy) , ionosphere , geophysics , magnetosphere , atmospheric sciences , astrophysics , magnetic field , plasma , chemistry , nuclear physics , organic chemistry , quantum mechanics
We report energetic particle (EPIC instrument) and magnetic field (MGF instrument) measurements collected onboard GEOTAIL located at ∼100 R E downstream in the magnetotail during a 13‐hour long active period on January 20–21, 1993. During this period, a series of 6 geomagnetic activity intensifications (breakup or pseudo‐breakup) have been studied with ground magnetograms and energetic particle data at geosynchronous orbit. We show that: (1) as a general trend, the level of the energetic ion fluxes was related to the intensity of the westward electrojet; (2) a systematic temporal (within a few minutes) correlation exists between energetic ion flux enhancements observed by GEOTAIL/EPIC in the distant tail and near‐Earth geomagnetic activity intensification onsets; and (3) for 5 of 6 cases, these energetic ion flux enhancements corresponded to strong tailward streams which included particles of both solar wind and ionospheric origin. Their amplitude seemed also to be related to the electrojet intensity change.