Re: [Phys-l] Poynting Vector

[Brian Whatcott <betwys1@sbcglobal.net>]

At 11:48 AM 6/28/2008, Jeffrey Schnick,  you wrote:
> Consider a charged simple parallel plate capacitor in a static uniform
> downward-directed magnetic field.  The capacitor is oriented so that
> from our point of view, the electric field between the plates of the
> capacitor is directed rightward.  Poynting tells us that between the
> plates, energy is flowing away from us at a rate proportional to EB.
> Where is that energy coming from and going to?

As Curtis O., intimates, you would expect a pulse of electromagnetic
 energy to radiate during the rise time of the capacitor charge
 current, or if it pre exists, during the rise time of the magnetic field.
This transient radiation energy is provided by the applied electric
current to capacitor or coil.


Brian Whatcott    Altus OK    Eureka!