Poynting Vector

(redirected from Poynting flux)

Poynting vector

[′pȯint·iŋ ‚vek·tər]
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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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:


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.