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| Titel |
Solar wind velocity distribution on the heliospheric current sheet during Carrington rotations 1787-1795 |
| VerfasserIn |
B. Bala, S. R. Prabhakaran Nayar |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 13, no. 8 ; Nr. 13, no. 8, S.807-814 |
| Datensatznummer |
250011954
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| Publikation (Nr.) |
 copernicus.org/angeo-13-807-1995.pdf |
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| Zusammenfassung |
| The solar wind velocity distribution in the
heliosphere is best represented using a v-map, where velocity contours
are plotted in heliographic latitude-longitude coordinates. It has already been
established that low-speed regions of the solar wind on the source surface
correspond to the maximum bright regions of the K-corona and the neutral line of
the coronal magnetic field. In this analysis, v-maps on the source
surface for Carrington rotations (CRs) 1787–1795, during 1987, have been
prepared using the interplanetary scintillation measurements at Research
Institute of Atmospherics (RIA), Nagoya Univ., Japan. These v-maps were
then used to study the time evolution of the low-speed (\leq450 km s–1)
belt of the solar wind and to deduce the distribution of solar wind velocity on
the heliospheric current sheet. The low-speed belt of the solar wind on the
source surface was found to change from one CR to the next, implying a time
evolution. Instead of a slow and systematic evolution, the pattern of
distribution of solar wind changed dramatically at one particular solar rotation
(CR 1792) and the distributions for the succeeding rotations were similar to
this pattern. The low-speed region, in most cases, was found to be close to the
solar equator and almost parallel to it. However, during some solar rotations,
they were found to be organised in certain longitudes, leaving regions with
longitudinal width greater than 30° free of low-speed solar wind,
i.e. these regions were occupied by solar wind with velocities greater than 450
km s–1. It is also noted from this study that the low-speed belt, in
general, followed the neutral line of the coronal magnetic field, except in
certain cases. The solar wind velocity on the heliospheric current sheet (HCS)
varied in the range 300–585 km s–1 during the period of study, and
the pattern of velocity distribution varied from rotation to rotation. |
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