Schematic of the Earth’s bow shock (deep blue). The Sun is at the top of the figure, out of view. The schematic view is looking down on the bow shock and magnetosphere (shaded gray area). At the Earth’s distance from the Sun, the interplanetary magnetic field lines have an angle of ∼45° relative to the Earth-Sun line. These magnetic field lines are indicated by the light blue lines. The bow shock is quasi-parallel on the morning side, quasi-perpendicular on the afternoon side, and oblique at the shock nose at noon. Foreshock electrons are indicated by the yellow dots and foreshock ions by the orange dots. The figure is taken from Tsurutani & Rodriguez (1981).