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Geomagnetic activit...
Geomagnetic activity effects on plasma sheet energy conversion
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- Hamrin, Maria (författare)
- Umeå universitet,Institutionen för fysik
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- Norqvist, Patrik (författare)
- Umeå universitet,Institutionen för fysik
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Marghitu, Octav (författare)
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- Buchert, Stephan C. (författare)
- Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen
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Klecker, Berndt (författare)
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Kistler, Lynn M (författare)
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Dandouras, Iannis (författare)
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(creator_code:org_t)
- 2010-10-01
- 2010
- Engelska.
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 28, s. 1813-1825
- Relaterad länk:
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https://umu.diva-por... (primary) (Raw object)
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https://urn.kb.se/re...
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https://doi.org/10.5...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- In this article we use three years (2001, 2002, and 2004) of Cluster plasma sheet data to investigate what happens to localized energy conversion regions (ECRs) in the plasma sheet during times of high magnetospheric activity. By examining variations in the power density, E·J, where E is the electric field and J is the current density obtained by Cluster, we have studied the influence on Concentrated Load Regions (CLRs) and Concentrated Generator Regions (CGRs) from variations in the geomagnetic disturbance level as expressed by the Kp, the AE, and the Dst indices. We find that the ECR occurrence frequency increases during higher magnetospheric activities, and that the ECRs become stronger. This is true both for CLRs and for CGRs, and the localized energy conversion therefore concerns energy conversion in both directions between the particles and the fields in the plasma sheet. A higher geomagnetic activity hence increases the general level of energy conversion in the plasma sheet. Moreover, we have shown that CLRs live longer during magnetically disturbed times, hence converting more electromagnetic energy. The CGR lifetime, on the other hand, seems to be unaffected by the geomagnetic activity level. The evidence for increased energy conversion during geomagnetically disturbed times is most clear for Kp and for AE, but there are also some indications that energy conversion increases during large negative Dst. This is consistent with the plasma sheet magnetically mapping to the auroral zone, and therefore being more tightly coupled to auroral activities and variations in the AE and Kp indices, than to variations in the ring current region as described by the Dst index.
Ämnesord
- NATURVETENSKAP -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- Energy conversion
- load
- generator
- Earth's magnetosphere
- geomagnetic activity
- Kp
- AE
- Dst
- Space physics
- Rymdfysik
- rymdfysik
- Space Physics
- Physics
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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