Auroral boundaries convey important information about the state of the magnetosphere. There have been numerous studies of the statistical behavior of these boundaries, but little is known about their relative latitudinal positions. We have conducted a survey of the NASA FAST satellite data, focusing on roughly meridional auroral "transits", allowing the comparison of relative latitudes of the boundaries at roughly the same magnetic local time. We focused on night-side transits as our objectives

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... relate to the night-side magnetospheric topology and dynamics. We identifed three boundaries (inner edge of the ion plasma sheet, ion isotropy boundary, and polar cap boundary) for roughly 10,600 night-side auroral zone transits. The inner edge and isotropy boundaries are well ordered by magnetic activity (indicated by Kp index), and that the separation in latitude between the boundaries is highly variable. The results are discussed in terms of their dependence on magnetic local time and geomagnetic activity.