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| Titel |
The response of the magnetosphere to the passage of a coronal mass ejection on March 20-21 1990 |
| VerfasserIn |
J. R. Taylor, Mark Lester, T. K. Yeoman, B. A. Emery, D. J. Knipp, D. Orr, S. I. Solovyev, T. J. Hughes, H. Lühr |
| 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 ; 15, no. 6 ; Nr. 15, no. 6, S.671-684 |
| Datensatznummer |
250012827
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| Publikation (Nr.) |
 copernicus.org/angeo-15-671-1997.pdf |
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| Zusammenfassung |
| The geomagnetic response to the passage of a
coronal mass ejection (CME) is studied. The passage of the CME resulted in a
storm sudden commencement (SSC) at 2243 UT on March 20 1990 with disturbed
magnetic activity during the following 24 h. The auroral, sub-auroral and
equatorial magnetic response to the southward turning at 1314 (±5) UT on March
21 and the equatorial response to the southward turning associated with the SSC
on 20 March are discussed in terms of existing models. It is found that the
auroral and sub-auroral response to the southward turning associated with the
SSC is a factor 2 or more quicker than normal due to the shock in the solar wind
dynamic pressure. The low-latitude response time to the southward turning,
characterised by Dst and the magnetopause current corrected Dst*,
is unaffected by the shock. Dst and Dst*, characteristic of the
equatorial magnetic field, responded to the 1314 (±5) UT southward turning
prior to the first observed substorm expansion phase onset, suggesting that a
dayside loading process was responsible for the initial enhancement in the ring
current rather than nightside particle injection. The response time of the
auroral and sub-auroral magnetic field to the southward turning at 1314 (±5) UT
on March 21 is measured at a variety of longitudes and latitudes. The azimuthal
propagation velocity of the response to the southward turning varied
considerably with latitude, ranging from ~8 km s–1 at 67°N to ~4 km s–1 at 55°N. The southward velocity of the equatorward
boundary of the northern polar convection pattern has been measured. This
velocity was ~1.2 km s–1 at 1600 MLT, although there was evidence
that this may vary at different local times. |
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