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| Titel |
Current system associated with small dipolarization fronts |
| VerfasserIn |
Laurianne Palin, Christian Jacquey, Hermann Opgenoorth, Martin Connors, Victor Sergeev, Jean-André Sauvaud, Rumi Nakamura, Geoffrey D. Reeves, Howard Singer, Vassilis Angelopoulos, Lucile Turc |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103081
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| Publikation (Nr.) |
 EGU/EGU2015-2480.pdf |
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| Zusammenfassung |
| We present a case study of eight successive Plasma Sheet (PS) activations (usually referred to
as « Bursty Bulk Flows » or « Dipolarisation Fronts ») associated with small individual
BZGSM increases on 31 March 2009 (0200 - 0900 UT). This series of events happens during
generally very quiet SW conditions, over a period of 7 hours preceding a substorm onset at
1230 UT. The amplitude of the dipolarizations increases with time. The low amplitude
dipolarization fronts are associated with few (1 or 2) Rapid Flux Transfer events
(Eh > 2mV/m), whereas the large amplitude ones engulf many more RFT events. All PS
activations are associated with a small and localised current wedge(« wedgelet ») which
seems to be the consequence of RFT arrival in the near tail. Ground magnetic perturbations
affect a larger part of the contracted auroral oval for the events with more RTF event
embedded (> 5). Dipolarisation Fronts with very low amplitude, a type usually not
included in statistical studies, are of particular interest because we found them
associated with clear wedgelets and particle injections at geosynchronous orbit. This
exceptional dataset highlights the role of flow bursts in the magnetotail and brings
up the question: are we in this case observing the smallest form of a substorm ? |
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