Re: Poynting Vector Vortex Experiment

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 3/9/02 1:52:30 PM Eastern Standard Time, tesla-at-pupman-dot-com
writes:



>
> > What I simply propose is take a look at EM as a three dimensional
> > entity rather than in two dimensions. 
>
> Correction:  EM is a 4-D Lorentz-invariant theory.  The math is much
> simpler when written down against a 4-D co-ordinate system, you
> just end up with a single neat and simple equation that describes
> the whole lot.  In 4-D, the separate vectors of E and B are clearly
> seen as a single field entity, described by an object called a
> 'tensor' rather than a 'vector'.  After the initial obstacle of
> learning tensor calculus (as if vector calculus wasn't hard enough!)
> the payback in terms of greater clarity of the theory is worthwhile.
> The relation between E, B, space, time, and the observer of the field
> becomes much simpler and clearer. 
>
> > Instead of just E and B there is always an attached S vector. 
>
> The S vector is called the Poynting vector and is *defined* to be
> E x H  (to be read as E cross H, where 'cross' is the vector cross
> product).  It isn't another component of the field, but relates to
> E and H in the same way that length and breadth relate to area, or
> that volts and current relate to power.  The S vector points in the
> direction of energy flow.  Just like you can have real power and
> reactive (or complex) power, you can define a complex S vector, E x H*
> where H* is the complex conjugate of H.  Integrate S to obtain the
> energy density of the field.
>
> > All three oriented at right angles.  Just like the 3D space we live
> > in, they are always inextricably linked
>
> Another misdirection: Richard is trying to make out that S is a third
> polarisation vector, on the same footing as E and B, rather than
> simply their cross product.  It is like confusing voltage and power.
>
> > This additional coordinate in the system doesn't exclude common EM
> > theory, but vastly enhances it.
>
> The Poynting vector, and Poynting's theorem, which describes the law
> of energy conservation in an EM field, are well established parts of
> EM theory.
>
> > Poynting also worked out the mathematics of an additional vector,
> > S, in relation to E and B.  He was ignored and forgotten.
>
> Another misdirection.  Look in any book on EM theory to find a chapter
> on the Poytning vector and its applications.  The Poynting vector is
> used extensively in things like antenna design.
>
> > The important thing is to realize the relationships of S = B x E are
> > universally there all the time.
>
> Correction: S = E x H.   If you use  H x E or B x E, the resulting
> vector points the opposite way.  The vector cross product
> anti-commutes, ie H x E = -(E x H).  We defined S to be E x H, so
> it's there for as long as we want it to be.  We defined it that way
> so that it represents the power flow in the field.
> --
> Paul Nicholson
> --
>
>



Shame on you Paul!
        How could you? Don't you realize by now that a good discussion is
ruined by someone joining in who actually knows what he is talking about??
;-))))
         In other words, Thanks for the clear-headed corrections and
explanations. They are long overdue. 

Matt D.