Figure 6. Earth’s magnetosphere is shaped and controlled by the Sun. (a) Schematic representation of the magnetosphere. Blue lines represent magnetic fields, and red lines represent currents. Magnetic connection is shown on the day side of the magnetosphere, where a southward-pointing interplanetary field merges with a northward-pointing geomagnetic field.
(b) Data from eight observatories show the disturbed horizon- tal intensity H during the Halloween magnetic storm of 28–31 October 2003. The magnetograms are arranged by longi- tude; red traces correspond to low-magnetic-latitude observa- tories and blue lines to observatories at high latitudes. The initial (I), main (M), and recovery (R) phases are discussed in the text. The circled anticorrelations between high- and low- latitude magnetograms are indicative of substorms.