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An Electron‐Scale Current Sheet Without Bursty Reconnection Signatures Observed in the Near‐Earth Tail
Author(s) -
Wang Rongsheng,
Lu Quanming,
Nakamura Rumi,
Baumjohann Wolfgang,
Huang Can,
Russell Christopher T.,
Burch J. L.,
Pollock Craig J.,
Gershman Dan,
Ergun R. E.,
Wang Shui,
Lindqvist P. A.,
Giles Barbara
Publication year - 2018
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 - 10.1002/2017gl076330
Subject(s) - current sheet , electron , heliospheric current sheet , current (fluid) , physics , plasma sheet , electric field , electric current , magnetic reconnection , current density , geophysics , magnetic field , atomic physics , condensed matter physics , magnetohydrodynamics , magnetosphere , solar wind , interplanetary magnetic field , quantum mechanics , thermodynamics
Observations of a current sheet as thin as the electron scale are extremely rare in the near‐Earth magnetotail. By measurement from the novel Magnetospheric Multiscale mission in the near‐Earth magnetotail, we identified such an electron‐scale current sheet and determined its detailed properties. The electron current sheet was bifurcated, with a half‐thickness of nine electron inertial lengths, and was sandwiched between the Hall field. Because of the strong Hall electric field, the super‐Alfvénic electron bulk flows were created mainly by the electric field drift, leading to the generation of the strong electron current. Inevitably, a bifurcated current sheet was formed since the Hall electric field was close to zero at the center of the current sheet. Inside the electron current sheet, the electrons were significantly heated while the ion temperature showed no change. The ions kept moving at a low speed, which was not affected by this electron current sheet. The energy dissipation was negligible inside the current sheet. The observations indicate that a thin current sheet, even as thin as electron scale, is not the sufficient condition for triggering bursty reconnection.