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| Titel |
Non-maxwellian features of magnetosheath ion distribution associated with mirror waves |
| VerfasserIn |
Jan Soucek, C. Philippe Escoubet |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048277
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| Zusammenfassung |
| The ion distribution function of magnetosheath plasma often exhibits a significant
temperature anisotropy T-¥ > T-¥. This anisotropy can induce plasma instabilities and give
rise to ultra low frequency (ULF) plasma waves, such as the mirror waves. The mirror waves
quickly grow to very large amplitudes and evolve into non-periodic plasma structures called
mirror modes. Theoretical and numerical studies suggest that trapped ion population is the
key element in the saturation of the mirror instability and non-linear evolution of mirror
modes. Previous experimental studies mostly used moments of the ion distribution function to
analyze this phenomenon. In this work we used the full 3D ion distribution measurements
from Cluster spacecraft to study the details of the ion distribution during intervals of
ULF wave activity. We show that the plasma strongly deviates from a standard
bi-maxwellian model and we demonstrate the presence of trapped particles correlated with
mirror mode field fluctuations. The results are compared with existing models. |
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