Date: 11 Mar 2010
Satellite: Cluster
Copyright: Credit: Image courtesy of Q.-G. Zong, Peking University, China & University of Massachusetts Lowell, USA)

This figure dramatically illustrates the effect on the Earth's magnetosphere of the arrival of an interplanetary shock. A huge increase in the number of energetic electrons and in the intensity of the electric field is clearly seen to coincide with the arrival of the shock front.

From top to bottom: (panel a) energetic electron spectrum recorded by one of the Cluster spacecraft (C1) on 7 November 2004 from 1800 to 1900 UT; electron spatial distributions measured by the other three Cluster spacecraft C2 (panel b), C3 (panel c) and C4 (panel d) with the electric field overplotted as a black line, and (panel e) B_z magnetic field component measured on all 4 spacecraft. The dashed red vertical line marks the time of arrival of the shock-induced field disturbances.