Three-dimensional structure and kinetic features of reconnection exhaust jets

Abstract

The structure of exhaust jets produced by a magnetic reconnection source region of width ∼3 RE in the out-of-plane direction is investigated with 3-D particle-in-cell simulations. The jet is found to separate into two segments, with the dawnward portion propagating ahead of, and expanding duskward in front of, the duskward one. In such conditions, an orbiting spacecraft would encounter repeated sharp Bz increases. Both segments exhibit east-west structures on scales of a few ion inertia lengths. The narrow Jy current sheets that produce the sharp Bz increases are associated with electron flows. The ion temperature components Tixx and Tiyy display markedly different behaviors, with the former exhibiting maxima both downstream and, in some locations, upstream of the front, while the latter exhibits maxima along the y extended front. The maximum load factor E·J at the front is several times larger in 3-D than in 2-D, is concentrated in numerous sub-ion-scale enhancements, and includes a significant ion dissipation contribution.