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| Titel |
Observations of whistler waves in solar wind with Cluster mission |
| VerfasserIn |
C. Lacombe, O. Alexandrova, A. Mangeney, M. Berthomier |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067527
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| Zusammenfassung |
| We study magnetic field fluctuations with the STAFF instrument onboard Cluster spacecraft.
The Spectral Analyser of STAFF allows to make measurements in the [8 - 4000]Â Hz
frequency range. Taking into account the instrumental noise level, magnetic spectra up to
 ~ 400 Hz are resolved. A large statistical study of nearly 200 intervals in the free solar
wind, during the first 5 years of the Cluster mission, shows the presence of whistler emissions
in ~ 10% of the studied cases. These waves have a direction of propagation quasi-parallel to
the mean magnetic field, and a polarisation quasi-circular and right-handed. Their
appearance in the solar wind is sometimes related to sudden changes in the proton density
and temperature, and always related to changes in the magnetic field direction.
The presence of these magnetic whistler waves could thus be related to magnetic
sector boundaries or to stream interaction regions : using electric field waveforms on
Stereo, Breneman et al. (2010) have found large amplitude whistler waves, obliquely
propagating with a large electrostatic component, at stream interaction regions.
We look at the pitch angle distributions of electrons when magnetic whistlers are
observed. |
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