Schematic view showing bow shock, magnetopause, magnetosphere, waves
The supersonic particles (mainly electrons and protons) of the solar wind suddenly slow down when they reach the bow shock. They then flow around the Earth's magnetic field in a region known as the magnetosheath. The boundary between the magnetosheath and the Earth's magnetic bubble (the magnetosphere) is called the magnetopause. Here, the interaction between the solar wind particles and the Earth's magnetic field results in a series of waves. These waves on the magnetopause travel away from the Sun at a speed of about 145 kms-1. The approximate position of the Cluster satellites, at the boundary between the magnetosphere and magnetosheath, is marked with the symbol at top left.