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| Titel |
Kinetic thin current sheets: their formation in relation to magnetotail mesoscale turbulent dynamics |
| VerfasserIn |
A. P. Kropotkin, V. I. Domrin |
| 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. 4 ; Nr. 27, no. 4 (2009-04-01), S.1353-1361 |
| Datensatznummer |
250016461
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1353-2009.pdf |
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| Zusammenfassung |
| Dynamics of the magnetotail plasma sheet (PS) features nonlinear
structures on two totally different scales. There are very thin
current sheets (CS) on kinetic scale of the ion gyroradius. And
there are intense plasma flow and magnetic field variations on
mesoscales (a few earth radii); those are interpreted as mostly 2-D
MHD turbulence. On the other hand, the specific nature of slow
large scale magnetotail evolution leads to large differences in
the PS properties and those of the lobe plasma. As a result, while
fast reconnection bursts in the tail provide quasi-stationary fast
mesoscale reconfigurations in the lobes, they cannot however be
accompanied by restructuring of CS on the same fast time scale.
Violations of force balance in the PS are thus generated.
Simulation using a hybrid code and starting with such imbalance,
provides an evidence of very thin kinetic CS structures formation,
embedded into the much thicker PS. The momentum balance gets
locally restored by means of ion acceleration up to the
Alfvénic velocity. The process provides an effective mechanism
for transformation of magnetic energy accumulated in the
magnetotail, into energy of plasma flows. The fast flows may drive
turbulence on shorter spatial scales. In their turn, these motions
may serve as an origin for new neutral line generation, and
reconnection. Application to substorm phenomenology is discussed. |
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