Formation of inner structure of a reconnection separatrix region.
We present multipoint spacecraft observations at the dayside magnetopause of a magnetic reconnection separatrix region. This region separates two plasmas with significantly different temperatures and densities, at a large distance from the X line. We identify which terms in the generalized Ohm's law balance the observed electric field throughout the separatrix region. The electric field inside a thin approximately c/omega pi Hall layer is balanced by the j x B/ne term while other terms dominate elsewhere. On the low density side of the region we observe a density cavity which forms due to the escape of magnetospheric electrons along the newly opened field lines. The perpendicular electric field inside the cavity constitutes a potential jump of several kV. The observed potential jump and field aligned currents can be responsible for strong aurora.
Khotyaintsev
Yu V
YV
Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden.
Vaivads
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Retinò
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André
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Owen
C J
CJ
Nilsson
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