Date: 08 Nov 2006
Satellite: Cluster
Depicts: Illustration of Cluster orbit and plasmasphere
Copyright: 'Windows to the Universe', http://www.windows.ucar.edu

At every orbit, the four Cluster spacecraft (C1, C2, C3, C4) have their perigee at around 4 Earth radii (1 Earth radius or R_E: 6371 km). Thus, the spacecraft fly systematically through the outer regions of the plasmasphere from south to north (see red dotted arrow), unless geomagnetic activity is so strong that the plasmasphere shrinks before being refilled and expanding back to its natural location.