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| Titel |
The interplay of the solar wind electron core and suprathermal populations. Temperature anisotropy instabilities |
| VerfasserIn |
Shaaban Mohammed Shaaban, Marian Lazar, Stefaan Poedts, Stepan Stverak, Milan Maksimovic, Atalla Elhanbaly |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143703
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| Publikation (Nr.) |
 EGU/EGU2017-7451.pdf |
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| Zusammenfassung |
| Despite the fact that the velocity distribution of electrons observed in the solar wind display a
dual structure with a thermal core and a suprathermal halo, the existing studies that
parametrized the electron temperature anisotropy and the resulting instabilities are limited to
idealized models, which incorporate the core and halo populations in a global bi-Kappa
model. Here we present the results from a more realistic study for the temperature anisotropy
instabilities conditioned by the interplay of the electron core and suprathermal halo
populations, when both these two populations may exhibit temperature anisotropies
Ac,h≠1. The analysis is based on the linearized kinetic Vlasov-Maxwell dispersion
relation for parallel wave propagation in homogeneous electron-proton plasmas. We
assume a bi-Maxwellian velocity distribution for the core (thermal) population, and a
bi-Kappa velocity distribution for the halo (suprathermal) population. We calculate the
growth rates, real frequency and the instability threshold conditions for different
halo-core relative density and various plasma properties. The effects of electron
suprathermal populations which are ubiquitous in the solar wind, are found to be
particularly important for a realistic characterization of the kinetic instabilities.
Important adjustments are obtained for the instability thresholds, which can explain the
limits of the temperature anisotropy reported for these populations in the solar wind. |
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