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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.

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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.