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| Titel |
Evolution of the dispersionless injection boundary associated with substorms |
| VerfasserIn |
T. Sarris, X. Li |
| 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 ; 23, no. 3 ; Nr. 23, no. 3 (2005-03-30), S.877-884 |
| Datensatznummer |
250015188
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| Publikation (Nr.) |
 copernicus.org/angeo-23-877-2005.pdf |
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| Zusammenfassung |
| One manifestation of energetic particle acceleration during magnetospheric
substorms is the sudden appearance of particle injections into the inner
magnetosphere, often observed near geosynchronous orbit. Injections that
show simultaneous flux increases in all energy ranges of a detector are
called dispersionless injections, and are most often observed in a narrow
region around local midnight. In these events it is assumed that the
satellite is located close to or inside the region where acceleration and/or
transport processes are taking place, called the injection region. We
present a study of the location, extent and temporal evolution of the
injection region, based on simulation results of a model of the expansion of
the electric and magnetic fields associated with a substorm. The model
simulates the fields during a substorm onset with an electric field and
consistent magnetic field pulse that propagates towards the Earth with a
decreasing speed. Our simulation shows that the dispersionless injection
boundary can be considered coincident with the leading edge of the pulse
field, which transports particles toward the Earth across a certain range of
local time. Under the same model field, the dispersionless injection
boundary shifts eastward for electrons and westward for protons, consistent
with the observation results deduced from statistical analysis of multiple
spacecraft measurements. |
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