Spacecraft Observations and Analytic Theory of Crescent-Shaped Electron Distributions in Asymmetric Magnetic Reconnection.
Supported by a kinetic simulation, we derive an exclusion energy parameter E_{X} providing a lower kinetic energy bound for an electron to cross from one inflow region to the other during magnetic reconnection. As by a Maxwell demon, only high-energy electrons are permitted to cross the inner reconnection region, setting the electron distribution function observed along the low-density side separatrix during asymmetric reconnection. The analytic model accounts for the two distinct flavors of crescent-shaped electron distributions observed by spacecraft in a thin boundary layer along the low-density separatrix.
Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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J
Egedal
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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Le
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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W
Daughton
Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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Wetherton
Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA.
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PA
Cassak
Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
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LJ
Chen
Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse, France, and Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France.
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B
Lavraud
University of New Hampshire, Durham, New Hampshire 03824, USA.
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RB
Torbert
Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
J
J
Dorelli
Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
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DJ
Gershman
Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
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Avanov