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Friday, 30 January 2015

Dipole Moment

dipole moment


In magneto statics the magnetic dipole magnet is obtained considering a coil of dimensions crossed by electric current. This is the first term in the multipole expansion of the magnetic field.

The size that characterizes mainly a magnetic dipole is the magnetic moment, which quantifies the tendency of the dipole to orientate in a given direction in the presence of an external magnetic field

It is a model equivalent to two opposite magnetic charges rigidly connected, in analogy with the electric dipole. Is realized by decreasing the size of a loop traversed by electric current, while maintaining constant the magnetic moment and taking the limit in which the area of the loop is zero.

The magnetic dipole is the simplest case of a 2p-pole, where 2p is the number of pole pairs, which for the magnetic Gauss's law is an integer. It is a useful schematization of the influence of a magnetic field on the coils very small current is passed through, and it is therefore used as part of the phenomenology of magnetism in the matter through classic atomic models (such as those of Rutherford and Bohr), through the 'introduction of atomic currents due to the motion of the electrons and currents caused by the Larmor precession of the orbit of these.