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Electron distribution functions in the electron diffusion region of magnetic reconnection: Physics behind the fine structures
Author(s) -
Bessho N.,
Chen L.J.,
Shuster J. R.,
Wang S.
Publication year - 2014
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 - 10.1002/2014gl062034
Subject(s) - physics , electron , magnetic reconnection , jet (fluid) , diffusion , momentum (technical analysis) , kinetic energy , momentum diffusion , distribution (mathematics) , distribution function , outflow , computational physics , classical mechanics , mechanics , magnetic field , nuclear physics , quantum mechanics , meteorology , turbulence , finance , economics , mathematical analysis , mathematics
Highly structured electron distribution functions in the electron diffusion region (EDR) during magnetic reconnection are studied by means of fully kinetic simulations. Four types of structures (striations, arcs, swirls, and rings) in momentum space are analyzed to understand their formation mechanisms. Discrete striations are formed by particles undergoing different numbers of meandering bounces in the EDR and are a result of oscillations in the out‐of‐plane force on meandering electrons. Predictions for the separation between striations and the triangular shape of the distribution are obtained analytically. Arcs and swirls are due to partial remagnetization of accelerated electrons. Near the end of the outflow jet, electron remagnetization gives rise to the ring structure. Understanding the distribution structures is critical to unraveling the kinetic processes occurring in the EDR and will guide the identification of EDRs based on satellite measurements.