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Auroral patches in the vicinity of the plasmapause
Author(s) -
Moshupi M. C.,
Cogger L. L.,
Wallis D. D.,
Murphree J. S.,
Anger C. D.
Publication year - 1977
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/gl004i001p00037
Subject(s) - plasmasphere , photometer , physics , electron , field line , equator , airglow , electron precipitation , substorm , geophysics , astrophysics , magnetic field , atomic physics , magnetosphere , atmospheric sciences , optics , astronomy , latitude , quantum mechanics
Unusual aurora‐like patches have been observed equatorward of the diffuse auroral boundary by the ISIS‐2 scanning auroral photometer. These rare features are observed predominantly in the evening sector and appear to corotate with the earth and to have lifetimes longer than two hours. Their occurrence coincides with positive going changes in the horizontal component of the earth's magnetic field (Dst). The patches are evidently excited mainly by electrons of energy somewhat higher than that of particles precipitating into the diffuse aurora (as evidenced by the lower average I(5577Å)/I(3914Å) ratio and the weakness of the red line (6300Å) emission). While intensities in the patches fall in the same range as in the "normal" auroras pole‐ward, total input power in a typical patch (10 8 watts) is a small fraction (.1%) of that in the auroral oval due to the different areas involved. The position of the patches leads to the conclusion that the particles creating them originate near the plasmapause.