On the source region and orientations of nightside auroral arcs

Using large data base of stable auroral arcs observed at Gillam we identified those passes of POES spacecraft which were magnetically conjugate to these arcs. We studied statistically arc locations with respect to the energetic particle isotropy boundaries (IBs), which are the well-known markers of the magnetotail regions. In the dusk and night sectors we confirm previous finding that arcs tend to appear close to or poleward of the electron …