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| Titel |
Occurrence and location of concentrated load and generator regions observed by Cluster in the plasma sheet |
| VerfasserIn |
M. Hamrin, P. Norqvist, O. Marghitu, S. Buchert, B. Klecker, L. M. Kistler, I. Dandouras |
| 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 ; 27, no. 11 ; Nr. 27, no. 11 (2009-11-04), S.4131-4146 |
| Datensatznummer |
250016698
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| Publikation (Nr.) |
 copernicus.org/angeo-27-4131-2009.pdf |
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| Zusammenfassung |
| Here, and in a companion paper by Hamrin et al. (2009) [Scale size
and life time of energy conversion regions observed by Cluster in
the plasma sheet], we investigate localized energy conversion
regions (ECRs) in the Earth's plasma sheet. In total we have studied
151 ECRs within 660 h of plasma sheet data from the summer and fall
of 2001 when Cluster was close to apogee at an altitude of about
15–20 RE. Cluster offers appropriate conditions for the
investigation of energy conversion by the evaluation of the power
density, E·J, where E is the
electric field and J the current density. From the sign
of the power density, we have identified more than three times as
many Concentrated Load Regions (CLRs) as Concentrated Generator
Regions (CGRs). We also note that the CLRs appear to be stronger. To
our knowledge, these are the first in situ observations
confirming the general notion of the plasma sheet, on the average,
behaving as a load. At the same time the plasma sheet appears to be
highly structured, with energy conversion occurring in both
directions between the fields and the particles. From our data we
also find that the CLRs appear to be located closer to the neutral
sheet, while CGRs prefer locations towards the plasma sheet boundary
layer (PSBL). For both CLRs and CGRs, E and J
in the GSM y (cross-tail) direction dominate the total power
density, even though the z contribution occasionally can be
significant. The prevalence of the y-direction seems to be weaker
for the CGRs, possibly related to a higher fluctuation level near
the PSBL. |
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