Cluster path through aurora region

The Cluster C3 and C1 satellite trajectories between 16:55 and 17:15 UT on 5 June 2009. During this period, both satellites were able to send back data about conditions in the auroral acceleration region of Earth’s dusk-side aurora. C3 flew through the region at an altitude of about 6,400 km (one Earth radius or RE), while C1 was flying at approximately 9,000 km (1.4 RE) and lagging about 5 minutes behind. The blue ovals indicate the poleward half of the auroral oval, which is characterised by upward currents in the dusk-side magnetic field.