| The theoretical value of the impact polarization of the Oxygen forbidden red line at 6300
ÅÂ was established by Bommier et al. (2011), while linear polarization was detected and
measured in this line of Earth aurorae by Lilensten et al. (2008) and Barthélemy et al. (2011).
In this work, we solve the statistical equilibrium of the line level population and alignment
(responsible for the linear polarization), taking into account all the processes entering the line
formation. We use production rates resulting from the TRANSSOLO model (Lilensten et al.,
2007) applied in the particular conditions of the observations. The resulting theoretical
polarization is found having order of magnitude in agreement with observations, and
depends on both the density and the velocity of the non-thermal electrons. This
would enable the diagnostic of one of these quantities via linear polarization degree
measurement. As for it, the linear polarization direction provides the aurorae magnetic field
direction.
References
Bommier, V., Sahal-Béchot, S. Dubau, J., and Cornille, M., Ann. Geophys., 29, 71-79,
2011
Barthélemy, M., Lilensten, J., Pitout, F., Simon Wedlund, Thissen, R., Lorentzen, D.,
Sigernes, F., Moen, J., Gronoff, G., McCrea, I., Rothkael, H., Ménager, H., and Aruliah, A.,
Ann. Geophys., 29, 1-12, 2011
Lilensten, J., Dudok de Wit, T., Amblard, P.O., Aboudarham, J., Auchère, F., and
Kretzschmar, M., 2007, Ann. Geophys., 25, 1299-1310
Lilensten, J., Moen, J., Barthélemy, M., Thissen, R., Simon, C., Lorentzen, D.A., Dutuit, O.,
Amblard, P.O., and Sigernes, F., Geophys. Res. Lett., 35, 8804, 2008 |