Pointing Vector

[kidia]

Can anybody give me the physical meaning of the pointing vector S=EXE for time varying fields. What are its units?

[Tom Mattson]

1.) It's the Poynting vector, named after the physicist John Henry Poynting.

 

2.) The Poynting vector is not [imath]\vec{E}\times\vec{E}[/imath]. If it were then it would be the zero vector! Rather, the Poynting vector is [imath]\vec{S}=\frac{1}{\mu_0}\vec{E}\times\vec{B}[/imath].

 

3.) You should be able to work out the units yourself. You should find that it has the units of intensity.

 

More:

 

http://en.wikipedia.org/wiki/Poynting_vector

http://scienceworld.wolfram.com/physics/PoyntingVector.html