Cluster observations of the polar outflows in the cusp regions with the continuously positive IMF B_x. (a) The total and three components of the IMF (in 4 minute resolution) measured by the MAG instrument on board ACE. (b) The velocity and number density of the ions (in 4 s resolution) measured by the CIS instrument on board Cluster. The yellow regions in (a) show the time interval during which the Cluster spacecraft passed through the cusp regions, and the data points are plotted in (b).