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| Titel |
Cluster observation of few-hour-scale evolution of structured plasma in the inner magnetosphere |
| VerfasserIn |
M. Yamauchi, I. Dandouras, H. Rème, R. Lundin, L. M. Kistler |
| 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 ; 31, no. 9 ; Nr. 31, no. 9 (2013-09-12), S.1569-1578 |
| Datensatznummer |
250086108
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| Publikation (Nr.) |
 copernicus.org/angeo-31-1569-2013.pdf |
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| Zusammenfassung |
Using Cluster Ion Spectrometry (CIS) data from the spacecraft-4 perigee
traversals during the 2001–2006 period (nearly 500 traversals after removing
those that are highly contaminated by radiation belt particles), we
statistically examined the local time distribution of structured trapped ions
at sub- to few-keV range as well as inbound–outbound differences of these ion
signatures in intensities and energy–latitude dispersion directions. Since
the Cluster orbit during this period was almost constant and approximately
north–south symmetric at nearly constant local time near the perigee,
inbound–outbound differences are attributed to temporal developments in
a 1–2 h timescale.
Three types of structured ions at sub- to few keV range
that are commonly found in the inner magnetosphere are examined:
– Energy–latitude dispersed structured ions at less than a few keV,
– Short-lived dispersionless ion stripes at wide energy range extending 0.1–10 keV,
– Short-lived low-energy ion bursts at less than a few hundred eV.
The statistics revealed that the wedge-like dispersed ions are most often
observed in the dawn sector (60% of traversals), and a large portion of them
show significant enhancement during the traversals at all local times. The
short-lived ion stripes are predominantly found near midnight, where most
stripes are significantly enhanced during the traversals and are associated
with substorm activities with geomagnetic AL < −300 nT. The low-energy
bursts are observed at all local times and under all geomagnetic conditions,
with moderate peak of the occurrence rate in the afternoon sector. A large
portion of them again show significant enhancement or decay during the
traversals. |
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