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Titel |
Source mechanism of Saturn narrowband emission |
VerfasserIn |
J. D. Menietti, P. H. Yoon, Ye Sheng-Yi, B. Cecconi, A. M. Rymer |
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 ; 28, no. 4 ; Nr. 28, no. 4 (2010-04-27), S.1013-1021 |
Datensatznummer |
250016823
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Publikation (Nr.) |
copernicus.org/angeo-28-1013-2010.pdf |
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Zusammenfassung |
Narrowband emission (NB) is observed at Saturn centered near 5 kHz and 20 kHz
and harmonics. This emission appears similar in many ways to Jovian
kilometric narrowband emission observed at higher frequencies, and therefore
may have a similar source mechanism. Source regions of NB near 20 kHz are
believed to be located near density gradients in the inner magnetosphere and
the emission appears to be correlated with the occurrence of large neutral
plasma clouds observed in the Saturn magnetotail. In this work we present
the results of a growth rate analysis of NB emission (~20 kHz) near or
within a probable source region. This is made possible by the sampling of
in-situ wave and particle data. The results indicate waves are likely to be
generated by the mode-conversion of directly generated Z-mode emission to
O-mode near a density gradient. When the local hybrid frequency is close n
fce (n is an integer and fce is the electron cyclotron frequency)
with n=4, 5 or 6 in our case, electromagnetic Z-mode and weak ordinary
(O-mode) emission can be directly generated by the cyclotron maser
instability. |
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