External Magnetic Field Produced By A Magnetic Dipole Moment
In classical physics, the magnetic field of a dipole is calculated as the limit of either a current loop or a pair of charges as the source shrinks to a point while keeping the magnetic moment m constant. For the current loop, this limit is most easily derived for the vector potential. Outside of the source region, this potential is (in SI units)
and the magnetic flux density (strength of the B-field) in teslas is
Alternatively one can obtain the scalar potential first from the magnetic pole limit,
and hence the magnetic field strength (or strength of the H-field) in ampere-turns per meter is
The magnetic field is symmetric under rotations about the axis of the magnetic moment.
Read more about this topic: Magnetic Dipole
Famous quotes containing the words external, magnetic, field, produced and/or moment:
“Language disguises the thought; so that from the external form of the clothes one cannot infer the form of the thought they clothe, because the external form of the clothes is constructed with quite another object than to let the form of the body be recognized.”
—Ludwig Wittgenstein (1889–1951)
“We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.”
—Henry David Thoreau (1817–1862)
“The frequent failure of men to cultivate their capacity for listening has a profound impact on their capacity for parenting, for it is mothers more than fathers who are most likely to still their own voices so they may hear and draw out the voices of their children.”
—Mary Field Belenky (20th century)
“In history an additional result is commonly produced by human actions beyond that which they aim at and obtain—that which they immediately recognize and desire. They gratify their own interest; but something further is thereby accomplished, latent in the actions in question, though not present to their consciousness, and not included in their design.”
—Georg Wilhelm Friedrich Hegel (1770–1831)
“Seas of bright juice suffuse heaven.
The earth by the sky staid with, the daily close of their junction,
The heav’d challenge from the east that moment over my head,
The mocking taunt, See then whether you shall be master!”
—Walt Whitman (1819–1892)