consider, with respect to electrodynamics that such a dipole moment.Elementary charge carriers flowing through the straight section of the conductors form a direct current.Accordingly, there is a current of said charge current (L * I, where I - current value, L - length of the section).In turn, Ampere's law considers two parallel current charge at L, tends to infinity.In the closed loop its two half have opposite in direction to the current forming a current dipole.Around each of the dipole generated vortex field, which is characterized by its own dipole charge current, oriented perpendicular to the plane in which the contour is located.It is called a dipole moment.But since we are considering only the current components, then to go to electromagnetism this term is called differently.Another name - the magnetic dipole moment (Pm, sometimes m).
He is one of the key characteristics of any substance.It is believed that the dipole moment arises due to the currents (as in the microcosm and in macrosystems).Under microcosm in this case refers to the atom: the moving in circular orbits charges (electrons) can be considered as an electrical current.Since matter consists of elementary particles, each of them also has its moment.Please note that under the elementary particles must be understood not only molecules and atoms, but also protons, neutrons, electrons, and possibly even smaller components.From the point of view of quantum mechanics, their magnetic dipole moment due to the inherent mechanical rotation - spin.However, this assumption in recent years have increasingly questioned in the light of modern field theory of particles.For example, it is generally accepted the existence of the so-called anomalous dipole whose value is different from the calculation equation in quantum theory.But with a field point of view, in which the magnetic field of any elementary particle is generated not by spin rotation of the charge carriers, and is one of the permanent components of the electromagnetic field, the anomalous dipole is easy to explain.The value is defined as a specific set of quantum numbers with the corrective part of the back.Thus, the magnetic moment of a neutron generating depends on its energy and the electric current changing electromagnetic field.
When calculating its value for a loop using the integral method of addition of the dipole moments of elementary current dipoles, creating a closed circular contour.
dipole moment in electrodynamics is determined by the formula:
Pm = S * I * n,
I - a value of current flowing;S - area of closed loop (circle);n - vector directed perpendicular to the plane in which the contour is located.While the above formula does not show it, of Pm and vector whose direction can be determined by well-known in the classical electrical engineering rule of thumb (right screw): if the rotation is an imaginary screw compared with the direction of current flow, the movement of the body of the screw coincides with the desired vector.
electric dipole field differs from that of a point charge, first of all, the configuration of the field lines.So from the point of view of physics, like a dipole is a balanced system of two electric charges, the modules are equal and opposite polarity (+ and -), the corresponding line of tension at the start of the charge, and the other end.In the case of a single point charge carrier lines diverge in all directions, like light bulbs.
