A Possible Polarization Mechanism of EUV Coronal Lines

Manso Sainz, R.; Trujilo-Bueno, J.
Bibliographical reference

Solar Polarization 5: In Honor of Jan Stenflo ASP Conference Series, Vol. 405, proceedings of the conference held 17-21 September, 2007 at Centro Stefano Franscini--Monte Veritá, Ascona, Switzerland. Edited by Svetlana V. Berdyugina, K. N. Nagendra, and Renzo Ramelli. San Francisco: Astronomical Society of the Pacific, 2009., p.423

Advertised on:
6
2009
Number of authors
2
IAC number of authors
0
Citations
7
Refereed citations
5
Description
The alignment generated in the ground level of Fe X by scattering in the coronal red line λ6374, can be efficiently transferred by collisions to upper levels; the ensuing spontaneous emission in allowed EUV transitions (as 174.5~Å and 177~Å) is then linearly polarized. The polarization thus generated would be sensitive to the electronic density (Ne) and to the magnetic field orientation although not to the field strength. At Ne˜ 10^7~cm-3 the linear polarization would be ˜1% just over the solar surface and ˜5% at 0.2R_&sun;, rapidly decaying for Ne> 10^8~cm-3. The mechanism works for other spectral lines and ions too.