ON THE STRUCTURE OF 3.11.94 ECLIPSE CORONA
M.M.Molodensky, L.I.Starkova and S. Koutchmy.
We present the results of our observations of the white-light corona
in polarized light performed at Criciuma eclipse, Brazil. During the observation
of 3.11.94 we have made five couple of pictures of the solar corona in
polarization light. The telescope with equatorial mounting with LOMO lens
diameter D = 7.5 cm and focus f = 75 cm used in the observation.
Fig.1. Optical scheme of the instrument.
To suppress the radial gradient of the coronal emission it was used
an mask of diameter d = 3 cm puted between the lens and the film
at a distance l = 25 cm from the focal plane. Radius R and
the focal length f of the lens were selected in such a way to provide
complete blinding of the lens at the moon edge and a full opening of the
lens at the distance g from the centre of the 6x6 cm picture.
Couples of pictures with exposures 2, 4, 8, 16 and 32 sec
were made. Revealed fine structure of the streamers allowed to perform
careful analysis of the solar corona structure.
Fig.2. Images of the corona in polarized light.
Fig.3. Computed stereo-diagram of the 3-D structure of the  =
0 surface. The polarization degrees are marked by the colors: red (
0 - 20%), yellow ( 21 - 40%), orange ( 41 - 60%), blue ( 61 - 80%), dark
blue ( 81 - 100%).
Fig.4. Plot of the polarization degree and structural drawing
of the corona for 3.11.96.
We propose new method of reconstructing the ray structure of the solar
corona for distances more than 1.5
from photosphere.
The method based on the calculation of the =0
surface. It was used the photospheric data as boundary conditions and assumed
potential approximation for the magnetic field with this approach, we have
built a =0
surface for 3.11.94. In our empirical model large streamers are represented
as folds and pleats of the thin geliospheric current sheet adjacent to
the = 0 surface.
In the present work we test the assumptions underlying our method of
calculating the coronal sheet near =
0 and compare the obtained results with the observations of the corona
of 3.11.94. Clear correspondence of the observed ray structures to the
configuration of the observed ray structures to the configuration of the
folds. This result is a very important confirmation of the adequacy of
the our approach.
The same conclusion can be derived from the analysis of the polarization
of main rays. The greatest of the polarization is observed for the points
located along the direction of the maximal extent of the corona.
References:
Koutchmy S., Molodensky M., Starkova L., Ershov A., Matsuura O.:
1995, Proceedings of the International Symposium on the Total Eclipse of
November 3, 1994. Revista de la Academia Nacional de Ciencias de
Bolivia 69, 60-71.
Molodensky M., Starkova L., Koutchmy S., Ershov A.: 1996,
Solar Drivers of Interplanetary and Terrestrial Disturbances ( Ed. K.S.Balasubramaniam,
S.Keil, and R.Smart ), 385-392.
Molodensky M.M., Starkova L.I., Koutvitsky V. and Ershov A.:
1996, Astronomicheskii Zhurnal, 73, 934-938.
Koutchmy S., Molodensky M.M., Starkova L.I. Koutvitsky V.
and Ershov A.: 1996, Izvestia VUZov, Radiofizika 39,
1381-1388.
Koutchmy S., Molodensky M.M., Starkova L.I. Koutvitsky V. and Ershov
A. : 1997, Pis'ma v Astronomicheskii Zhurnal, 23, 939-948.
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