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| Titel |
Electrodynamics in a very thin current sheet leading to magnetic reconnection |
| VerfasserIn |
N. Singh, C. Deverapalli, G. Khazanov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 13, no. 5 ; Nr. 13, no. 5 (2006-09-22), S.509-523 |
| Datensatznummer |
250011838
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| Publikation (Nr.) |
 copernicus.org/npg-13-509-2006.pdf |
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| Zusammenfassung |
| We study the formation of a very thin current sheet (CS) and associated
plasma electrodynamics using three-dimensional (3-D) particle-in-cell
simulations with ion to electron mass ratio M/m=1836. The CS is driven by
imposed anti-parallel magnetic fields. The noteworthy features of the
temporal evolution of the CS are the following: (i) Steepening of the
magnetic field profile Bx(z) in the central part of the CS, (ii)
Generation of three-peak current distribution with the largest peak in the
CS center as Bx(z) steepens, (iii) Generation of converging electric
fields forming a potential well in the CS center in which ions are
accelerated. (iv) Electron and ion heating in the central part of the CS by
current-driven instabilities (CDI). (v)
Re-broadening of the CS due to increased kinetic plasma pressure in the CS
center. (vi) Generation of electron temperature anisotropy with temperature
perpendicular to the magnetic field being larger than the parallel one.
(vii) Current disruption by electron trapping in an explosively
growing electrostatic instability (EGEI) and
electron tearing instability (ETI). (viii)The onset of EGEI coincides with
an increase in the electron temperature above the temperature of the
initially hot ions as well as the appearance of new shear in the electron
drift velocity. (ix) Bifurcation of the central CS by the current
disruption. (x) Magnetic reconnection (MR) beginning near the null in
Bx and spreading outward. (xi) Generation of highly energized electrons
reaching relativistic speeds and having isotropic pitch-angle distribution
in the region of reconnected magnetic fields. We compare some of these
features of the current sheet with results from laboratory and space
experiments. |
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