Noun
Poynting vector (plural Poynting vectors)
(electromagnetism) The vector obtained in the direction of a right-hand screw from the cross product (vector product) of the electric field vector rotated into the magnetic field vector of an electromagnetic wave. Note: The Poynting vector, with transmission media parameters and constants, gives the irradiance and direction of propagation of the electromagnetic wave. Mathematically:
P
→
=
E
→
×
H
→
{\displaystyle {\vec {P}}={\vec {E}}\times {\vec {H}}}
.
Although there are only static electric and magnetic fields, the calculation of the Poynting vector produces a clockwise circular flow of electromagnetic energy, with no beginning or end. Source: Internet
Antenna (radio) An isotropic antenna is an idealized " radiating element " used as a reference ; an antenna that broadcasts power equally (calculated by the Poynting vector ) in all directions. Source: Internet
Classical picture In classical Maxwell electrodynamics a phase-conjugating mirror performs reversal of the Poynting vector : : which is a linear momentum density of electromagnetic field, where (in) means incident field, (out) means reflected field. Source: Internet
Confusingly, the Poynting vector is sometimes called the power flux, which is an example of the first usage of flux, above. Source: Internet
For example, the Poynting vector within the dielectric insulator of a coaxial cable is nearly parallel to the wire axis (assuming no fields outside the cable and a wavelength longer than the diameter of the cable, including DC). Source: Internet
In the region around the battery the Poynting vector is directed outward, indicating power flowing out of the battery into the fields; in the region around the resistor the vector is directed inward, indicating field power flowing into the resistor. Source: Internet