TY - JOUR TI - On the formation of the high-altitude stagnant cusp: Cluster observations AV - public VL - 32 Y1 - 2005/06/16/ N1 - Copyright 2005 by the American Geophysical Union IS - 12 ID - discovery157927 N2 - On 16 March 2002, Cluster moved from nightside to dayside, across the high-altitude northern cusp during an extended period of relatively steady positive IMF BY and B-Z. Combined Cluster and SuperDARN data imply the existence of two reconnection sites: in the high-latitude northern hemisphere dusk and southern hemisphere dawn sectors. Within the cusp, Cluster encounters 3 distinct plasma regions. First, injections of magnetosheath-like plasma associated with dawnward and sunward convection suggest Cluster crosses newly-reconnected field lines related to the dusk reconnection site. Second, Cluster observes a Stagnant Exterior Cusp ( SEC), characterized by nearly isotropic and stagnant plasma. Finally, Cluster crosses a region with significant antifield-aligned flows. We suggest the observed SEC may be located on newly re-closed field lines, reconnected first poleward of the northern hemisphere cusp and later reconnected again poleward of the southern hemisphere cusp. We discuss how the Cluster observations correspond to expectations of 'double reconnection' model. SN - 0094-8276 PB - AMER GEOPHYSICAL UNION UR - http://dx.doi.org/10.1029/2005GL022813 JF - Geophysical Research Letters KW - Interplanetary magnetic-field KW - Boundary-layer KW - Reconnection KW - Magnetosphere KW - Magnetopause KW - Plasma A1 - Bogdanova, YV A1 - Marchaudon, A A1 - Owen, CJ A1 - Dunlop, MW A1 - Frey, HU A1 - Wild, JA A1 - Fazakerley, AN A1 - Klecker, B A1 - Davies, JA A1 - Milan, SE ER -