@article{discovery162631,
          number = {7},
         journal = {Geophysical Research Letters},
       publisher = {Amer Geophysical Union},
            year = {2006},
           title = {Temporal evolution of a staircase ion signature observed by Cluster in the mid-altitude polar cusp},
           month = {April},
          volume = {33},
            note = {Copyright 2006 by the American Geophysical Union},
             url = {http://dx.doi.org/10.1029/2005GL025598},
        abstract = {We use the Cluster string of pearls configuration to investigate temporal variations of ion precipitation in the mid-altitude polar cusp. On 7 Aug. 2004, Cluster 4 was moving poleward through the Northern cusp, followed by Cluster 1, Cluster 2, and finally Cluster 3. The Wind spacecraft detected a Southward turning of the Interplanetary Magnetic Field ( IMF) at the beginning of the cusp crossings and IMF-Bz stayed negative throughout. Cluster 4 observed a high energy step in the ion dispersion around 1 keV on the equatorward side of the cusp. C1, entering the cusp around 1 minute later, did not observe the high energy step anymore but a partial dispersion with a low energy cut-off reaching 100 eV. About 9 min later, C3 entered the cusp and observed a full ion dispersion from a few keV down to around 50 eV. The open-closed boundary, identified by electron precipitation, was initially moving equatorward at a rate of -0.43 degrees ILAT/minute at the beginning of the event and then slowed down to -0.16 degrees ILAT/minute, suggesting the erosion of the dayside magnetosphere under IMF Southward. This event is explained by the onset of dayside reconnection when the IMF turned southward; the step being the first signature of the reconnection that would then evolve as a full dispersion as reconnection goes on. We observed 1-3 keV ions near the open-closed boundary on the three spacecraft crossings that suggests a continuous reconnection during about 9 minutes.},
            issn = {0094-8276},
          author = {Escoubet, CP and Bosqued, JM and Berchem, J and Trattner, KJ and Taylor, MGGT and Pitout, F and Laakso, H and Masson, A and Dunlop, M and Reme, H and Dandouras, I and Fazakerley, A},
        keywords = {Flux-transfer events, Interplanetary magnetic-field, Low-altitude observations, Magnetopause reconnection, Precipitation, Aurora, Edge}
}