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| Titel |
On the Electron Dynamics during Rapid Asymmetric Magnetic Island Coalescence: Insights on the Electrons Agyrotropy with the Presence of a Guide Field |
| VerfasserIn |
Emanuele Cazzola, Giovanni Lapenta, Maria Elena Innocenti, Martin Goldman, David Newman, Stefano Markidis |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125157
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| Publikation (Nr.) |
 EGU/EGU2016-4696.pdf |
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| Zusammenfassung |
| The work presents a fully kinetic analysis of the electrons dynamics during rapid island
coalescence in asymmetric magnetic reconnection, especially focused on the comparison
between the case with and with no initial guide field. Formation and growth of
the islands are caused by an intentionally unstable initial configuration across the
current sheet with the same asymmetric profiles as those traditionally proposed in the
literature (e.g. Pritchett, 2008). Particular attentions is given to the different evolution
of the presumed reconnection sites. Three main regions are eventually identified,
named by X-, D- and M-regions, which describe, respectively, the regions featuring a
traditional reconnection event, those showing an opposite behavior with respect to
the former and the reconnection regions occurring between two magnetic islands
(Cazzola et al., 2015). Further analysis is mainly addressed to evaluate both the
electrons departure from the isotropic and gyrotropic behavior. Whether the first
quantity has been clearly established and confirmed by observations, the latter has
always appeared of difficult interpretation, and an ultimate accepted method on
how to render it from PIC simulations still seems far to be achieved. In light of the
upcoming data from the freshly launched MMS NASA mission, outcomes from some of
the main techniques to spot agyrotropic regions are here compared to highligh the
presence of possible relevant differences (Scudder and Daughton, 2008; Swisdak,
2015).
References
[1] P. Pritchett, “Collisionless magnetic reconnection in an asymmetric current
sheet,” Journal of Geophysical Research: Space Physics (1978–2012), vol. 113,
no. A6, 2008.
[2] E. Cazzola, M. E. Innocenti, S. Markidis, M. V. Goldman, D. L. Newman,
and G. Lapenta, “On the electron dynamics during island coalescence in
asymmetric magnetic reconnection,” Physics of Plasmas (1994-present), vol. 22,
no. 9, p. 092901, 2015.
[3] J. Scudder and W. Daughton, “Illuminating electron diffusion regions of
collisionless magnetic reconnection using electron agyrotropy,” Journal of
Geophysical Research: Space Physics (1978–2012), vol. 113, no. A6, 2008.
[4] M. Swisdak, “Quantifying gyrotropy in magnetic reconnection,” arXiv
preprint arXiv:1509.00787, 2015. |
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