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| Titel |
Energy deposition in the ionosphere through a global field line resonance |
| VerfasserIn |
I. J. Rae, C. E. J. Watt, F. R. Fenrich, I. R. Mann, L. G. Ozeke, A. Kale |
| 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 ; 25, no. 12 ; Nr. 25, no. 12 (2008-01-02), S.2529-2539 |
| Datensatznummer |
250015959
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| Publikation (Nr.) |
 copernicus.org/angeo-25-2529-2007.pdf |
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| Zusammenfassung |
| We present an interval whereby we can estimate the energy dissipation in the
ionosphere through an externally-driven field line resonance. In this paper, we
utilise an interval described in general by Rae et al. (2005), where the global
magnetospheric cavity was shown to be energised via a high solar wind speed
stream. Using the ground-based instrumentation available, we estimate the
spatial extent of the generated pulsations to be at least 10° in
latitude and 65° in longitude, a sizeable fraction of the dusk-sector
ionosphere. Using a fortuitous conjunction with the Polar spacecraft, we
compare point measurements of the net downward Poynting vector to the
estimated Joule heating rate in the ionosphere, and find that model values
of the Pedersen conductance are reasonable. In the interval of interest, we
estimate the total dissipation rate during a global field line resonance to
be comparable to that reported in substorm studies. Previous studies have
estimated the total energy deposition via field line resonance to be up to
4% of that deposited during a small substorm. However, in this paper we
find that the total energy deposited via Joule heating may actually be
30% or more of the energy deposited in the ionosphere during a substorm
cycle using a conservative estimate of the pulsation duration. |
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