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| Titel |
Magnetic field depression in electron holes |
| VerfasserIn |
Ivan Vasko, Oleksiy Agapitov, Forrest Mozer, Anton Artemyev |
| 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 |
250112820
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| Publikation (Nr.) |
 EGU/EGU2015-12999.pdf |
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| Zusammenfassung |
| We analyze spikes of the electrostatic field observed by Van Allen Probes in the outer
radiation belt. These spikes exhibit the classical signatures of electron holes, i.e. a positive
hump of the electrostatic potential (depleted electron density) and a propagation velocity of
the order of an electron thermal velocity. The characteristic amplitude, velocity and spatial
scale of these electron holes are several tens of mV/m, several thousand of km/s and about
several km, respectively. The unexpected feature is the magnetic field depression of about
several tens of pT within the observed electron holes. We suggest that this depression is due
to the diamagnetic current of an electron population trapped within the electron hole. We
estimate that the trapped population has a density up to 50% of the background
plasma density, a temperature of about hundreds of eV and a high temperature
anisotropy, T/¥/T/¥~ 3.5. We argue that the observed electron holes could be generated
due to the injection of the highly-anisotropic plasma into the outer radiation belts. |
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