Magnetic substorms, which were noted by E.C. Herrick, Kristian Birkeland, S.I. Akasofo and his mentor Sidney Chapman, are believed to represent the sudden conversion of magnetic energy to particle energy and may be associated with magnetic reconnection. This site compares magnetic storms with substorms. Whereas substorms are only observed in the auroral zone, magnetic storms are a world-wide phenomenon. Their magnetic disturbances on the ground are smaller, but the electrical currents which produce them may actually be much stronger. The dynamo process and its possible production of Birkeland currents are also discussed.