Earth’s magnetic dipole

Earth’s magnetic dipole

. The Earth’s magnetic field looks like that which would be produced by a bar magnet at the center of the Earth, with the North Magnetic Pole corresponding to the South Geographic Pole and vice versa. The Earth's magnetic dipole originates in swirling currents of molten iron deep in the Earth’s core, and extends more than 10 Earth radii , or 63.7 million meters out into space on the side facing the Sun, and all the way to the Moon's orbit, at 384.4 million meters on the opposite side. Magnetic field lines loop out of the South Geographic Pole and into the North Geographic Pole. The lines are close together near the magnetic poles where the magnetic force is strong, and spread out where it is relatively weak. The magnetic axis is tilted at an angle of 11.7 degrees with respect to the Earth’s rotational axis. This dipolar (two poles) configuration applies near the surface of the Earth, but further out the magnetic field is distorted by the solar wind (Fig. 3.12).

Copyright 2010, Professor Kenneth R. Lang, Tufts University