Green-Line
Polarization Observations
of the Solar Corona and Their Interpretation
O. G.
Badalyan*, M. A. Livshitz*, and J. S
kora**
* Institute of
Terrestrial Magnetism, Aeronomy, and Radiowave Propagation,
Russian Academy of Sciences,
Troitsk, Moscow Region 142092, Russia
**Astronomical Institute, Tatranska Lomnica, Slovak Republic
Received December 30, 1996
AbstractPolarization
observations in the
5303 Å FeXIV line during the eclipse of July
11, 1991 are presented. A new polarization map probing somewhat
greater heights in the corona is constructed, and the
distribution of polarization position angles is given. Low
degrees of polarization p are obtained in the equatorial
regions; at low heights, they are consistent with the results of
out-of-eclipse observations. The values for p are higher
in regions of high-latitude streamers, and increase substantially
with distance from the limb. The method used in the analysis made
it possible to separate the line emission into two components
(associated with excitation due to electron collisions and with
resonant scattering of the photospheric radiation), and also to
estimate the density and overall extent of the emitting region.
The observed values of p are consistent with current ideas
about the corona if the relative density of the FeXIV ion is 2
10
- 5 and the rate of excitation by electron collisions is 5
10
- 9 cm3/s. The possible role of magnetic fields
is briefly discussed.
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