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| Titel |
Systematic analysis of fine spectral structures of equatorial noise |
| VerfasserIn |
Z. Hrbáčková, O. Santolík, J. S. Pickett, D. A. Gurnett, N. Cornilleau-Wehrlin |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023431
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| Zusammenfassung |
| Equatorial noise is an intense wave emission generated by unstable ion distributions. It occurs
in the inner magnetosphere and propagates close to the geomagnetic equator at frequencies
between the local proton cyclotron and local lower hybrid frequencies. Recent studies have
shown that these waves could be capable of contributing to the local acceleration
of energetic electrons in the outer Van Allen belts. We use data obtained by the
onboard-analyzed STAFF-SA and high-resolution WBD instruments recorded by the four
Cluster spacecraft during the years 2002-2007. Systematic analysis of six years of
STAFF-SA data shows that equatorial noise is present at all magnetic local times. The
average occurrence rate is approximately 60%. We also present results obtained by the
systematic analysis of fine spectral structures in the equatorial noise emissions
observed by the WBD instrument. We show the probability density function (PDF) of
frequencies of emission peaks,which have been visually chosen from high-resolution
spectrograms, and the PDF of frequency intervals between the spectral lines. We match
these results with the ion cyclotron frequency as a function of the radial distance. |
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