Magnetic equator is the imaginary line near the geographic equator where Earth’s magnetic field is horizontal. The region around an object in which its magnetic influence can be detected is said to contain its magnetic field. A compasslike device called a dipping needle can be used to locate the magnetic equator. It consists of a magnetized needle that can rotate up and down. At the north magnetic pole, a dipping needle points down because the magnetic field is directed downward there. At the south magnetic pole, the needle points up. Roughly halfway between the magnetic poles, the needle will balance horizontally. The magnetic equator connects all the points on Earth’s surface where this occurs.
If Earth acted as a simple dipole (two-poled magnet), like an ordinary bar magnet does, the magnetic equator would form a simple circle halfway between the magnetic poles. However, Earth’s magnetic field is much more complex. As a result, the magnetic equator traces a gradually bending path.
Winds in the ionosphere, an electrically conducting layer of the atmosphere, generate electric currents as they flow past Earth’s magnetic field. These currents are particularly strong over the magnetic equator, where they are called the equatorial electrojet.
