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Communication Dans Un Congrès Année : 2011

Polarisation of auroral emission lines in the Earth's upper atmosphere : first results and perspectives

Résumé

Polarisation of light is a key observable to provide information about asymmetry or anisotropy within a radiative source. Following the pioneering and controversial work of Duncan in 1959, the polarisation of auroral emission lines in the Earth's upper atmosphere has been overlooked for a long time, even though the red intense auroral line (6300Å) produced by collisional impacts with electrons precipitating along magnetic field lines is a good candidate to search for polarisation. This problem was investigated again by Lilensten et al (2006) and observations were obtained by Lilensten et al (2008) confirming that the red auroral emission line is polarised. More recent measurements obtained by Barthélemy et al (2011) are presented and discussed. The results are compared to predictions of the theoretical work of Bommier et al (2011) and are in good agreement. Following these encouraging results, a new dedicated spectropolarimeter is currently under construction between BIRA-IASB and IPAG to provide simultaneously the polarisation of the red line and of other interesting auroral emission lines such as N2+ 1NG (4278Å), other N2 bands, etc... Perspectives regarding the theoretical polarisation of some of these lines will be presented. The importance of these polarisation measurements in the framework of atmospheric modeling and geomagnetic activity will be discussed.
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Dates et versions

hal-02382974 , version 1 (27-11-2019)

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H. Lamy, M. Barthelemy, C. Simon Wedlund, J. Lilensten, V. Bommier. Polarisation of auroral emission lines in the Earth's upper atmosphere : first results and perspectives. American Geophysical Union, Fall Meeting 2011, Dec 2011, San Francisco, United States. ⟨hal-02382974⟩
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