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| Titel |
The nightside magnetic field line open–closed boundary and polar rain electron energy-latitude dispersion |
| VerfasserIn |
S. Wing, Y. L. Zhang |
| 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 ; 33, no. 1 ; Nr. 33, no. 1 (2015-01-12), S.39-46 |
| Datensatznummer |
250121146
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| Publikation (Nr.) |
 copernicus.org/angeo-33-39-2015.pdf |
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| Zusammenfassung |
| The polar rain electrons near the open–closed field line boundary on the
nightside often exhibit energy-latitude dispersion, in which the energy
decreases with decreasing latitude. The solar wind electrons from the last
open-field line would E × B drift equatorward as they move
toward the ionosphere, resulting in the observed dispersion. This process is
modeled successfully by an open-field line particle precipitation model. The
existing method for determining the magnetotail X line distance from the
electron dispersion underestimates the electron path length from the X line
to the ionosphere by at least 33%. The best estimate of the path length
comes from using the two highest energy electrons in the dispersion region.
The magnetic field line open–closed boundary is located poleward of the
highest energy electrons in the dispersion region, which in turn is located
poleward of Defense Meteorological Satellite Program (DMSP) b6, b5e, and b5i boundaries. In the four events examined, b6
is located at least 0.7–1.5° equatorward of the magnetic field line
open–closed boundary. The energy-latitude dispersion seen in the electron
overhang may result from the plasma sheet electron curvature and gradient
drifts into the newly closed field line. |
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