sci.physics.electromag

On Mar 5, 7:26=A0am, "Bill Miller"
wrote:
>
>
> >>>> 2. What "basic observation" can you cite that proves that, for
> >>>> instance, an E field CAUSES an H field?
>
> >>> The fact that electro-magnets work.
>
> >> An electromagnet works because electrons are in motion; not because any=

> >> causal relationship exists between an electric field and a magnetic
> >> field.
>
> >> Such relationship cannot be causal because E fields and H fields exist
> >> simultaneously. The basic concept of causality is that A must precede B=

> >> in order for A to cause B.
>
> FrediFizzx:
>
> > Don't you think the E field from the electrons in motion help to make th=
e
> > B field of the electro-magnet?
>
> There is no *measured* evidence that demonstrates any such relationship.
> There have been numerous attempts and they have all had null results. =A0F=
or a
> nice summary, see D.F. Bartlett, "Conduction and the magnetic field in a
> circular capacitor." Am. J. physics 58, 1168-1172 (1990)
>
> >Do you think the magnetic field of the electrons in motion are enough to
> >make the total mag field of the electro-magnet?
>
> As near as I have been able to determine, the only way that a magnetic fie=
ld
> can exist is through the motion of charges. This appears to be the case in=

> permanent magnets also, but I have not seen rigorous theory -- as well as
> empirical evidence -- to support this contention.

Yes, and charges without E or epsilon mean no H.