Magnetic dipole moment

Summary

The magnetic dipole moment of a current distribution is the vector that measures its strength and orientation as a small magnet. For a flat current loop it is the current times the area, along the normal to the loop. Far from the currents, the magnetic field is to leading order that of a magnetic dipole, decaying like the inverse cube of the distance. It also gives the torque and the energy of the distribution in a uniform external field.