fair-weather electric current

The fair-weather electric current is equivalent to a leaking current occuring between two spherical plates. That is, the space charge moves downward through the atmosphere (dielectric) between the ionosphere and Earth (plates). This net downward transport of positive charge occurs in a current between 1,350 to 1,800 amperes over the entire Earth's surface. Those studying atmospheric electricity hypothesize that lightning causes this fair-weather electric current by bringing negative charge to ground (keeping the spherical capacitor charged). If lightning did not occur continuously, the Earth-ionosphere capacitor would lose its current in less than 10 minutes.