This drawing shows the difference between a dipole and a magnetosphere.
Click on image for full size
Image from the AGU Educator's Slide set. Image copyright 1997 by the American Geophysical Union. Further electronic distribution is not allowed.

A Planetary Magnetosphere

A planetary magnetosphere is different from an ordinary dipole. The force of the solar wind, coming from the sun stretches the dipole and creates a nose region in the front of the magnetosphere (facing the sun), and a tail region in the back called a magnetotail.

If it weren't for the solar wind, a planet's magnetic field would extend forever. But because the solar wind presses upon a planet's magnetic field, and encloses it, the magnetic field is forced to stay within a "cavity" called the magnetosphere.

This magnetosphere naturally has a boundary and that boundary is called the magnetopause.

Last modified June 23, 2010 by Randy Russell.

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