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Electron Diffusion Regions in Magnetotail Reconnection Under Varying Guide Fields
Author(s) -
Chen L.J.,
Wang S.,
Hesse M.,
Ergun R. E.,
Moore T.,
Giles B.,
Bessho N.,
Russell C.,
Burch J.,
Torbert R. B.,
Genestreti K. J.,
Paterson W.,
Pollock C.,
Lavraud B.,
Le Contel O.,
Strangeway R.,
Khotyaintsev Yu V.,
Lindqvist P.A.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl082393
Subject(s) - physics , magnetic reconnection , current sheet , electron , magnetic field , diffusion , field line , computational physics , perpendicular , population , field (mathematics) , plasma sheet , geophysics , magnetosphere , magnetohydrodynamics , quantum mechanics , geometry , mathematics , demography , sociology , pure mathematics
Kinetic structures of electron diffusion regions (EDRs) under finite guide fields in magnetotail reconnection are reported. The EDRs with guide fields 0.14–0.5 (in unit of the reconnecting component) are detected by the Magnetospheric Multiscale spacecraft. The key new features include the following: (1) cold inflowing electrons accelerated along the guide field and demagnetized at the magnetic field minimum while remaining a coherent population with a low perpendicular temperature, (2) wave fluctuations generating strong perpendicular electron flows followed by alternating parallel flows inside the reconnecting current sheet under an intermediate guide field, and (3) gyrophase bunched electrons with high parallel speeds leaving the X‐line region. The normalized reconnection rates for the three EDRs range from 0.05 to 0.3. The measurements reveal that finite guide fields introduce new mechanisms to break the electron frozen‐in condition.