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Magnetospheric Multiscale Observation of an Electron Diffusion Region at High Latitudes
Author(s) -
Burkholder B. L.,
Nykyri K.,
Ma X.,
Rice R.,
Fuselier S. A.,
Trattner K. J.,
Pritchard K. R.,
Burch J. L.,
Petrinec S. M.
Publication year - 2020
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 - 10.1029/2020gl087268
Subject(s) - magnetosheath , magnetopause , current sheet , magnetosphere , physics , bow shock (aerodynamics) , magnetic reconnection , geophysics , solar wind , plasma sheet , heliospheric current sheet , electron , instability , computational physics , diffusion , magnetic field , magnetohydrodynamics , shock wave , interplanetary magnetic field , mechanics , quantum mechanics , thermodynamics
On 17 October 2016, Magnetospheric Multiscale (MMS) sampled an electron diffusion region (EDR) embedded in an electron‐scale current sheet within a mixed portion of the high‐latitude magnetosheath adjacent to the magnetopause. We analyze the generalized Ohm's law, dissipation, and electron velocity distributions inside the EDR. The velocities, magnetic fields, and densities observed in the magnetosheath and magnetosphere indicate the magnetopause was unstable to the Kelvin‐Helmholtz instability, which can form electron‐scale current sheets. Alternatively, a current sheet was observed in the solar wind at L1 40 min before the MMS observations, which could have been compressed by the bow shock initiating reconnection. Hundreds of keV particles near the EDR may have been locally accelerated.