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| Titel |
The structure of strongly tilted current sheets in the Earth magnetotail |
| VerfasserIn |
I. Y. Vasko, A. V. Artemyev, A. A. Petrukovich, R. Nakamura, L. M. Zelenyi |
| 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 ; 32, no. 2 ; Nr. 32, no. 2 (2014-02-20), S.133-146 |
| Datensatznummer |
250121027
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| Publikation (Nr.) |
 copernicus.org/angeo-32-133-2014.pdf |
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| Zusammenfassung |
| We investigate strongly tilted (in the y–z GSM plane) current sheets
(CSs) in the Earth magnetotail using data from the Cluster mission. We
analyze 29 CS crossings observed in 2001–2004. The characteristic current
density, magnetic field at the CS boundary and the CS thickness of strongly
tilted CSs are similar to those reported previously for horizontal (not
tilted) CSs. We confirm that strongly tilted CSs are generally characterized
by a rather large northward component of the magnetic field. The
field-aligned current in strongly tilted CSs is on average two times larger
than the transverse current. The proton adiabaticity parameter,
κp, is larger than 0.5 in 85% of strongly tilted CSs
due to the large northward magnetic field. Thus, the proton dynamics is
stochastic for 18 current sheets with 0.5 < κp < 3 and protons
are magnetized for 6 sheets with κp > 3, whereas electrons are
magnetized for all observed current sheets. Strongly tilted CSs provide a
unique opportunity to measure the electric field component perpendicular to
the CS plane. We find that most of the electric field perpendicular to the CS
plane is due to the decoupling of electron and ion motions (plasma
polarization). For 27 CSs we determine profiles of the electrostatic
potential, which is due to the plasma polarization. Drops in the potential
between the neutral plane and the CS boundary are within the range of 200 V
to 12 kV, while maximal values of the electric field are within the range of
0.2 mV m−1 to 8 mV m−1. For 16 CSs the observed potentials are
in accordance with Ohm's law, if the electron current density is assumed to
be comparable to the total current density. In 15 of these CSs the profile of
the polarization potential is approximately symmetric with respect to the
neutral plane and has minimum therein. |
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