The structure of the distant magnetotail, where the closed field line region terminates, is investigated in the framework of several models and on the basis of laboratory simulations of the interaction of a flowing magnetized plasma with a dipole field. From our simulations we find that this region for northward ''interplanetary'' field (IMF) resembles that of a quasi-static tail structure, in which a flaring tail transits into a nonflaring current sheet configuration at a location where the internal pressure is balanced by the external plasma and magnetic pressures only. This structure is associated with a Y-type magnetic neutral line. The magnetic tail apparently includes an open field line region, despite the fact that this magnetosphere did not have a history of southward IMF, which could have opened the dipole field through frontside reconnection. This is a strong indication of the occurrence of high-latitude nightside reconnection, suggested by Dungey (1963). For southward model IMF the closed field line region appears to terminate at an X-type magnetic neutral line, as in the standard open magnetosphere model of Dungey (1961). This configuration is also in qualitative agreement with the simple superposition of a dipole field and a uniform IMF and with the presence of a plasma mantle which expands through drifts from the magnetosphere boundary toward the plasma sheet and becomes partially trapped through magnetic reconnection at the distant X line. ¿ American Geophysical Union 1992