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Astron. Astrophys. 349, 295-300 (1999)

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Relationship between polarization and intensity of the green line in different coronal structures

O.G. Badalyan 1, M.A. Livshits 1 and J. Sýkora 2

1 Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, 142092 Troitsk, Russia (badalyan/livshits@izmiran.troitsk.ru)
2 Astronomical Institute, SK-05960 Tatranská Lomnica, Slovak Republic (sykora@ta3.sk)

Received 3 February 1999 / Accepted 17 June 1999


The effect of anticorrelation between the polarization and intensity of the coronal green line Fe XIV 530.3 nm, revealed by the July 11, 1991 eclipse observations, is investigated. To simplify the general character of this effect, we have created the diagrams p versus [FORMULA] for the points inside a narrow ring, at fixed distances from the solar disk centre. In this case, the global anticorrelation dependence disintegrated into two branches with `a void zone' between them. The subsequent analysis has shown that the points, corresponding to the individual coronal structures of different types, are clustered in specific places of the diagram. While the upper branch is related to the huge high-latitude streamers, the lower branch contains the equatorial coronal condensations of different brightness. These branches are best evident at the distance [FORMULA] 1.2 [FORMULA], and they vary with the distance from the disk centre. Model calculations, performed within the scope of generally accepted concepts, cannot explain the observed peculiarities of the anticorrelation dependence, in particular, the presence of the gap between the two branches. The way out of these difficulties could be sought in assuming that the coronal magnetic field affects the generation of the polarized radiation in the emission green line.

Key words: eclipses – Sun: corona – polarization – magnetic fields

Send offprint requests to: J. Sýkora

© European Southern Observatory (ESO) 1999

Online publication: August 25, 1999