INTERNATIONAL JOURNAL OF GEOMAGNETISM AND AERONOMY VOL. 5, GI2011, doi:10.1029/2004GI000069, 2004

Measurements of brightness and nonradial direction of coronal streamers according to data of SOHO/Large Angle and Spectrometric Coronagraph Experiment (LASCO)-C2

Gun-Der Kim, V. I. Makarov, and A. G. Tlatov
Kislovodsk Solar Station of the Pulkovo Observatory, St. Petersburg, Russia


Abstract

[1]  Daily observations of the corona were processed according to the data of coronagraph SOHO/Large Angle and Spectrometric Coronagraph Experiment (LASCO)-C2 to study the variations of brightness and nonradial direction of coronal streamers during 1996.5-2003.5. Photometry of coronal images was carried out at heights of 2.3 Rodot-5.5 Rodot with a step of 2o along position angle. The total number of processed days has been about 4300. The latitude-time distributions of coronal intensity were analyzed at different heights. The maximum brightness of the corona was observed in the equatorial zone in the solar minimum. The drifts of coronal intensity were observed in direction to the poles in the beginning of solar cycle. The maximum brightness of high-latitude corona was observed during the polar magnetic field reversal of the Sun in 1999-2001. The drifts of low coronal brightness were observed in the opposite direction from high latitudes to the equator after polar magnetic field reversal. The angles of deviation from radial direction of coronal streamers were determined on daily coronal images. It was found that coronal streamers were inclined on the whole to the equator during 1996.5-1999.5, although after 1999.5 the streamers were inclined to the poles. The angles of nonradial direction of the streamers reached about 10o-15o. The longitudinal distribution of coronal brightness at various heights was considered. It was compared with heliosphere neutral layer and with drift of filament bands in an epoch of polar magnetic field reversal of the Sun.

Received 9 April 2004; revised 7 October 2004; accepted 17 November 2004; published 28 December 2004.

Keywords: Solar corona; coronal rays; coronal observations.

Index Terms: 7509 Solar Physics, Astrophysics, and Astronomy: Corona; 7524 Solar Physics, Astrophysics, and Astronomy: Magnetic fields; 7536 Solar Physics, Astrophysics, and Astronomy: Solar activity cycle.


AGU

Citation: Kim, Gun-Der, V. I. Makarov, and A. G. Tlatov (2004), Measurements of brightness and nonradial direction of coronal streamers according to data of SOHO/Large Angle and Spectrometric Coronagraph Experiment (LASCO)-C2, Int. J. Geomagn. Aeron., 5, GI2011, doi:10.1029/2004GI000069.

Copyright 2004 by the American Geophysical Union

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