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Polar rain aurora
Author(s) -
Zhang Yongliang,
Paxton Larry J.,
Lui Anthony T. Y.
Publication year - 2007
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 - 10.1029/2007gl031602
Subject(s) - polar , dusk , electron precipitation , magnetosheath , physics , polar cap , ionosphere , flux (metallurgy) , solar wind , atmospheric sciences , magnetosphere , geophysics , astrophysics , magnetopause , astronomy , plasma , materials science , quantum mechanics , metallurgy
Global FUV auroral imagers (IMAGE/SI‐13 and DMSP/SSUSI) observed, for the first time, two similar auroral events in the southern polar cap due to intense (keV) polar rain electrons from the solar wind as observed by DMSP and Geotail. Such an aurora is called polar rain aurora. The polar rain aurora could fill the dayside polar cap initially and developed a dawn‐dusk alignment while they moved anti‐sunward. The associated IMF B z was mostly southward. The IMF B x changed from negative to positive for the first event and stayed positive for the second event. The strong IMF B y was associated with the two events. The dawn‐dusk alignment of polar rain aurora might be due to the dawn‐dusk aligned magnetic flux tubes in the magnetosheath caused by the dominant IMF B y and modulation of the keV electrons by the nonoscillatory drift mirror waves and pitch angle diffusion via the electron cyclotron instability.