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Titel |
Cluster observations and theoretical identification of broadband waves in the auroral region |
VerfasserIn |
M. Backrud-Ivgren, G. Stenberg, M. André, M. Morooka, Y. Hobara, S. Joko, K. Rönnmark, N. Cornilleau-Wehrlin, A. Fazakerley, H. Rème |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 23, no. 12 ; Nr. 23, no. 12 (2005-12-23), S.3739-3752 |
Datensatznummer |
250015437
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Publikation (Nr.) |
copernicus.org/angeo-23-3739-2005.pdf |
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Zusammenfassung |
Broadband waves are common on auroral field lines. We use two different
methods to study the polarization of the waves at 10 to 180 Hz observed by
the Cluster spacecraft at altitudes of about 4 Earth radii in the nightside
auroral region. Observations of electric and magnetic wave fields, together
with electron and ion data, are used as input to the methods. We find that
much of the wave emissions are consistent with linear waves in homogeneous
plasma. Observed waves with a large electric field perpendicular to the
geomagnetic field are more common (electrostatic ion cyclotron waves), while
ion acoustic waves with a large parallel electric field appear in smaller
regions without suprathermal (tens of eV) plasma. The regions void of
suprathermal plasma are interpreted as parallel potential drops of a few
hundred volts. |
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