PLASMA SHEET. “Because the reconnection region is limited in the cross-tail direction, the flow shear between the fast outflow from the reconnection region and the ambient Earthward plasma flow within the plasma sheet creates a pair of field-aligned current sheets, where the current flows to the ionosphere at the eastern edge of the reconnection region and out from the ionosphere at the western edge.”
https://link.springer.com/article/10.12942/lrsp-2007-1