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| Titel |
Characteristics of variations in the ground magnetic field during substorms at mid latitudes |
| VerfasserIn |
K. L. Turnbull, J. A. Wild, F. Honary, A. W. P. Thomson, A. J. McKay |
| 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 ; 27, no. 9 ; Nr. 27, no. 9 (2009-09-01), S.3421-3428 |
| Datensatznummer |
250016639
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3421-2009.pdf |
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| Zusammenfassung |
| Substorms are known to cause geomagnetically induced currents
(GIC) in power transmission lines through variations in the ground magnetic
field. An improved knowledge and understanding of how the different phases of
substorms affect the ground magnetic field will ultimately help to better
understand how GIC arise. Although usually associated with high latitude
power transmission networks, GIC potentially pose a risk to mid latitude
networks such as the UK's National Grid. Using a list of substorm expansion
phase onsets derived from auroral observations by the IMAGE-FUV satellite,
this study examines 553 individual onsets. In order to cover mid latitudes,
ground magnetometer data from the UK Sub-Auroral Magnetometer Network
(SAMNET) are exploited. These high time resolution (5 s) data are used to
study the ground magnetic field for an hour after onset, in particular the
time derivative of the horizontal magnetic field, H. The data covers the
period from 2000 to 2003 (just after solar maximum). Results are compared
with a previous study of magnetic field variations at higher latitudes, using
data with a much lower (1 min) cadence during substorms identified from
geomagnetic indices during a period just after solar minimum. |
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