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Read Full Article (file size: 377385 bytes) Cited by
GEOPHYSICAL RESEARCH LETTERS,
VOL. 35,
L08804,
doi:10.1029/2007GL033006,
2008
Polarization in aurorae: A new dimension for space environments studies
Jean Lilensten
CNRS-UJF, Laboratoire de Planétologie de Grenoble, Bâtiment D de physique, Grenoble, France
Jøran Moen
Department of Physics, University of Oslo, Blindern, Oslo, Norway ESTEC, Noordwijk, Netherlands
Mathieu Barthélemy
CNRS-UJF, Laboratoire de Planétologie de Grenoble, Bâtiment D de physique, Grenoble, France
Roland Thissen
CNRS-UJF, Laboratoire de Planétologie de Grenoble, Bâtiment D de physique, Grenoble, France
Cyril Simon
CNRS-UJF, Laboratoire de Planétologie de Grenoble, Bâtiment D de physique, Grenoble, France ESTEC, Noordwijk, Netherlands
Dag A. Lorentzen
Arctic Geophysics, University Centre in Svalbard, Longyearbyen, Svalbard, Norway
Odile Dutuit
CNRS-UJF, Laboratoire de Planétologie de Grenoble, Bâtiment D de physique, Grenoble, France
Pierre Olivier Amblard
CNRS-INPG, GIPSA Lab, BP 46, Saint Martin d'Hères, France
Fred Sigernes
Arctic Geophysics, University Centre in Svalbard, Longyearbyen, Svalbard, Norway
Abstract
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
Received 14
December
2007;
accepted 14
March
2008;
published 19
April
2008.
Keywords: thermosphere;
polarization;
aurora.
Index Terms: 2427 Ionosphere: Ionosphere/atmosphere interactions (0335); 2407 Ionosphere: Auroral ionosphere (2704); 3369 Atmospheric Processes: Thermospheric dynamics (0358); 5729 Planetary Sciences: Fluid Planets: Ionospheres (2459); 7999 Space Weather: General or miscellaneous.
Read Full Article (file size: 377385 bytes) Cited by
Citation: Lilensten, J., J. Moen, M. Barthélemy, R. Thissen, C. Simon, D. A. Lorentzen, O. Dutuit, P. O. Amblard, and F. Sigernes
(2008),
Polarization in aurorae: A new dimension for space environments studies,
Geophys. Res. Lett.,
35,
L08804,
doi:10.1029/2007GL033006.
Copyright 2008 by the American Geophysical Union.
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