Magnetic poles are the positive and negative sides of a magnetic system. Unlike electric charges, which can be separated into positive charges that have no corresponding negative charge and vice versa, magnetic poles do not exist in isolation. In other words, there is no such thing as a magnetic monopole. The magnetic component of the electromagnetic force is such that everything that is magnetized has positive and negative, or north and south, poles. This phenomenon can be observed with a handful of kitchen magnets: there will always be one side of a magnet that attracts and one side that repels, a given other magnet side. One of the basic principles of magnetics is that like poles repel and unlike poles attract.

The most common arrangement of magnetic poles is the dipole. This is a simple, linear polar arrangement, with a north pole on one side and...