Plasma sheet formation during long period of northward IMF

We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event observed on October 23, 2003 by the Cluster spacecraft. We find that high-latitude reconnection occurs tailward of both cusps between the IMF and geomagnetic field. The newly created closed magnetic flux tubes capture magnetosheath plasma, and subsequently sink and shrink into the magnetosphere, while convecting tailward. The plasma that enters near the reconnection site is driven sunward and toward the low latitude region initially; it then drifts to the flanks. The captured plasma is characterized by small flow velocity, and it is moderately heated in the reconnection region. In the present case study we find the cold plasma enters the plasma sheet in the near Earth tail where it is observed by Cluster.