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Polarization in aurorae: A new dimension for space environments studies
Author(s) -
Lilensten Jean,
Moen Jøran,
Barthélemy Mathieu,
Thissen Roland,
Simon Cyril,
Lorentzen Dag A.,
Dutuit Odile,
Amblard Pierre Olivier,
Sigernes Fred
Publication year - 2008
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 - 10.1029/2007gl033006
Subject(s) - polarization (electrochemistry) , physics , geophysics , space physics , planet , thermosphere , planetary science , ambiguity , electron precipitation , astronomy , polar , computational physics , magnetic field , astrobiology , ionosphere , magnetosphere , linguistics , chemistry , philosophy , quantum mechanics
The polarization of emission lines is a noteworthy observational parameter in astronomy. However, it has never been detected without ambiguity in planetary upper atmospheres. Theoretical considerations have suggested that the polarization of the thermospheric oxygen red line (630 nm) could exist in the polar cap region. We present here its first successful measurement at Svalbard in January 2007, during active geophysical conditions. We assign its origin and variability to complementary effects between permanent low‐energy electron precipitation and sporadic auroral events. Implications in physics, geophysics and planetary science are foreseen. In physics, it raises the question of the polarization of a forbidden transition by electron impact which is still unknown. In geophysics, it provides a new parameter to constrain the thermospheric models. In planetary science, it makes it possible to derive the local configuration of the magnetic fields. It therefore opens new perspectives for future space missions towards other planets