Poynting Vector


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Poynting vector

[′pȯint·iŋ ‚vek·tər]
(electromagnetism)
A vector, equal to the cross product of the electric-field strength and the magnetic-field strength (mks units) whose outward normal component, when integrated over a closed surface, gives the outward flow of electromagnetic energy through that surface.

Poynting Vector

 

the vector of the flux density of electromagnetic energy; named after the English physicist J. H. Poynting (1852–1914).

The magnitude of the Poynting vector is equal to the energy transferred per unit time through a unit of surface perpendicular to the direction of propagation of the electromagnetic energy, that is, to the direction of the Poynting vector. In the absolute (Gaussian) system of units, Π = (e/π)[EH], where [EH] is the vector product of the intensities of the electric flux E and magnetic field H and c is the speed of light in a vacuum; in the International System, Π = [EH]. The flow of the Poynting vector through a closed surface bounding a system of charged particles gives the value of the energy lost by the system per unit time as a result of the emission of electromagnetic waves. The momentum density of an electromagnetic field g is expressed in terms of the Poynting vector:

G. IA. MIAKISHEV

References in periodicals archive ?
The photons correspond to an energy flow along the direction of propagation in 3-space resulting from the Poynting vector.
Find the properties for the field lines of the Poynting vector field [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII.
In the surrounding medium the time-averaged Poynting vector corresponding to [w.
According to the principle of interference, the observable Poynting vector is given by the incoherent vector sum of its components in the forward and reverse components, and thus it is impermissible to express the near-zone irradiance of the field as the squared magnitudes of scalar wave functions.
where r is the radius vector, S the Poynting vector, and [s.
The latter are further used in spatial integrations which lead to a net electric charge q = 0 and net magnetic moment M [not equal to] 0, as expected, and into a nonzero total mass m [not equal to] 0 due to the mass-energy relation by Einstein, as well as to a nonzero spin s [not equal to] 0 obtained from the Poynting vector and equation (8).
There was shown that the average Poynting vector of superposition field involves the intensities of the transverse electromagnetic and the optical fields which form the intensity of light diffraction.
This is evident from the Poynting vector that has only two components, one along the particle motion and the other along the electric field direction.
Finally the integrated angular momentum is obtained from the Poynting vector, as given by
According to Schiff [8] and Heitler [9] the Poynting vector then defines the momentum of the pure radiation field, expressed by sets of quantized plane waves.