[SI-LIST] Re: how EM wave propagates through space
- From: "Kevin G. Rhoads" <kgrhoads@xxxxxxxxxxxx>
- Date: Tue, 04 Oct 2011 14:53:49 -0400
>My question is related to propagation of EM waves.
Wave propagation is like resonance waves with a spatial component.
In resonance, energy "sloshes" from one mode to another. So for an elastic
wave on a rope, one energy storage mode is elastic, the other kinetic, and
energy sloshes back and forth between the two modes.
In a travelling wave the sloshing between modes is coupled with displacement
in space. So the wave, instead of sitting still and energy sloshing more or
less in place (standing wave), the sloshing of energy between modes is always
coupled with an average motion in one direction (travelling wave).
There is no way to describe this more exactly in natural language. The
proper language for exact description is mathematical.
For E&M waves, the two energy storage modes are electric and magnetic.
Energy sloshes back and forth between these two modes. In an L-C circuit,
this gives rise to resonance. In a transmission line you can have standing
waves, travelling waves and various mixed modes. And in free-space propagation,
it is like the transmission line, only without needed conductors nor
dielectrics.
If a hand-waving answer suffices, then this, with what others have said already
should do for you. If this does not suffice, then you must grok the equations.
HTH
Kevin
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
