abstract_textpThe magnetic field topology of the plasma sheet boundary layer (PSBL) and its neighborhood is examined using a steady, two-dimensional (2-D), ideal MHD reconstruction method. We study four PSBL crossings, from the lobe toward the plasma sheet and back into the lobe, by the Cluster spacecraft in the Earth's magnetotail around (x, y, z)=(-17.3, 4.3, -6.3) R-E in GSM. The four PSBL events are selected for having no intense ion beams. Two reconstructed magnetic field topologies give, for the first time, a 3-D view of the PSBL, showing that one has a rather large gradient in the magnetic structure than another. A quantitative agreement of the current density between the reconstruction and curlometer methods is achieved for the overall results but with some discrepancies remaining, which will be discussed in terms of 3-D and temporal effects. This agreement indicates that the current density can be estimated by the reconstruction if certain conditions are satisfied. Finally, we point out that a PSBL structure with intense ion beams would somehow degrade the accuracy of the ideal MHD reconstruction. This degradation may be due to the nonideal MHD properties and/or the transient properties of the ion beams. Further sophisticated investigations on this issue are needed for clarification./p/abstract_text
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