sci.physics.electromag

On Mar 4, 9:55=A0pm, Timo Nieminen wrote:
> On Tue, 4 Mar 2008, xray4abc wrote:
> > I think now that it does.
> > Simple experiments, performed by Oleg D. Jefimenko and others
> > have shown electric field-lines around the wiring of some electric
> > circuits.
> > (see references in 'The electric force of a current" by A.K.T. Assis
> > and
> > J.A.Hernandes ).
> > These force-field lines are different from the ones that would exist
> > if
> > no current is flowing through the circuit.
>
> I wouldn't put it that way around, but would instead say that an electric
> field is needed to create an electric current.
>
> Ch2 in Assis has some nice figures showing the kind of surface charge
> distributions one would expect. He is correct to point out that there must=

> be a component of the Poynting vector parallel to the wire, as well as the=

> more commonly mentioned perpendicular component of the Poynting vector. If=

> there were not, how could energy travel from the power supply to outside
> some part of the wire in order to move into it?

I got an idea to be verified experimentally!
The electric field around a conductor through which a current flows,
seems to be one where rotE<>0 .
Then an adequately situated conductor -loop could show an
"induced "-like electric current through it !
(I have not considered the influence of the conductor-loop on
the original electric field structure)
>
> > Interestingly, O.d. Jefimenko does not consider the current as a
> > source of electric field.
> > He mentions 3 sources of an electric field : 1. charge density
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A02.the
> > time derivative of charge density
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A03.the
> > time derivative of current density J
> > My question is meant for those who are familiar with the mentioned
> > authors'
> > approach to the theory of electromagnetism.
>
> It's just a case of 1, the surface charge density (again, well-illustrated=

> in Assis). Current in a resistive circuit doesn't just flow by itself.
>
> --
> Timo Nieminen - Home page:http://www.physics.uq.edu.au/people/nieminen/
> E-prints:http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
> Shrine to Spirits:http://www.users.bigpond.com/timo_nieminen/spirits.html

Regards, LL