Jefimenkoo, Panofskyy, Phillips And All The Rest
Bill Miller
charge density and current. These equations show that it is not possible for
an E field to *cause* an H field and vice versa. Wikipedia's link is:
http://en.wikipedia.org/wiki/Jefimenko%27s_equations
In spite of this evidence, it appears to me that most of the Electrical
Engineering community as well as much of the Electromagnetic Physics
community - including many on this list - cling to the viewpoint that E
causes H and H causes E.
So I did some reading to see if I could better understand this puzzling
dichotomy.
Subsequent to Jefimenko's initial publication of these equations in the
early 90s, Kirk McDonald published a thoughtful piece entitled, "The
relation between expressions for time-dependent electromagnetic fields given
by Jefimenko and by Panofsky and Phillips, American Journal of Physics 65
(11) (1997), 1074-1076'. This can be viewed at:
http://puhep1.princeton.edu/~mcdonald/examples/jefimenko.pdf
In light of the apparent antecedents, why is Jefimenko's "discovery" so
controversial? And why, in Jefimenkp's otherwise well-sourced book
(Causality,,,) does P&P's prior art *not appear*?
To attempt to understand why, I purchased P&P's text for reading as I headed
to Hemry's Fork for several days of world class Trout fishing. On the
flight, I began to understand at least part of the puzzle.
P&P's expressions for Maxwell's equations in terms of charges and currents
are found in Chapter 14. While Jefimenko uses a variety of vector identities
and deductive reasoning to achieve his results, P&P use a bit more
straightforward (in my opinion) Fourier transform process,
Their results, after adjusting for nomenclature differences, are
*identical.*
But it turns out that P&P were not the first to have these insights. Kirk
did a little "detective work" and uncovered prior art dating back to the30's
in the form of a paper by Stratton and Chu (of "Chu limit" antenna fame?)
that contains one of the two expressions relating E and H to currents and
charges.
So.. in introducing "Jefimenko's Equations," did the author simply miss
prior art. Or did he ignore it?
We may never know.
But maybe a "hint" is contained ib P&P's rendition of Maxwell's equations
into Hamiltonians. Prior to doing si, P&P make the following pronouncement:
In describing the electromagnetic field, (24-3) P&P state unequivocally (and
without proof) that ".energy oscillates between electric and magnetic
energy,,,"
Since Jefimenko clearly understood that this was *not* the case im an EM
wave. it would be logical; (and wntirely human)l for him to not cite this
work as a reference.
And this makes the folliowing question perhaps germane: In view of an 80+
year history during which it has been understood clearly rhat E does not
*cause* H and H does not *cause* E, why in the world would anyone think that
it did!
BTW. On another newsgroup, several posters cstegorically ignored Jefimenko's
propositions regarding Gravitation stating that since Jefmenko had not
provided a Hamiltonoan "proof" of the hypothesis/, Jefimenko's
Gravitational Equations - with one minus sugn - have been shown to be valid
by P&P, shall we consider Jefimenko's Gravitational Equations to supercede
those of Newton anf Einsteinm?
All The Best
Bill Millerr
FrediFizzx
news:8c6uac...@mid.individual.net...
> Jefiimenko's Equations show the relationship between E Fields, H
> Fields, charge density and current. These equations show that it is
> not possible for an E field to *cause* an H field and vice versa.
> Wikipedia's link is:
>
> http://en.wikipedia.org/wiki/Jefimenko%27s_equations
>
> In spite of this evidence, it appears to me that most of the
> Electrical Engineering community as well as much of the
> Electromagnetic Physics community - including many on this list -
> cling to the viewpoint that E causes H and H causes E.
Do you have a reference for your claimed statistics? :-) Not many
physicists that I know of think that the E and B fields of EM radiation
cause each other. Nor do I. But that does not mean in certain
situations that a B field CAN'T cause an E field. Toss a bar magnet
thru a loop of wire.
> So I did some reading to see if I could better understand this
> puzzling dichotomy.
I suspect you are trying to make a mountain out of a mole hill. Yes...
there are some erroneous statements in some of the literature but I
don't think you will find those kind of statements in current
electrodynamics textbooks such as Griffiths or Jackson.
> Subsequent to Jefimenko's initial publication of these equations in
> the early 90s, Kirk McDonald published a thoughtful piece entitled,
> "The relation between expressions for time-dependent electromagnetic
> fields given by Jefimenko and by Panofsky and Phillips, American
> Journal of Physics 65 (11) (1997), 1074-1076'. This can be viewed at:
>
>
>
> http://puhep1.princeton.edu/~mcdonald/examples/jefimenko.pdf
>
>
>
> In light of the apparent antecedents, why is Jefimenko's "discovery"
> so controversial? And why, in Jefimenkp's otherwise well-sourced book
> (Causality,,,) does P&P's prior art *not appear*?
Not sure why you continue to think his discovery is so controversial.
It is not. As I told you before, his equations are simply the
time-dependent generalizations of Coulomb's law and of the Biot-Savart
law and are the causal solutions to the Maxwell Equations for E and B
fields. Why would there be anything controversial about that?
> To attempt to understand why, I purchased P&P's text for reading as I
> headed to Hemry's Fork for several days of world class Trout fishing.
> On the flight, I began to understand at least part of the puzzle.
>
>
>
> P&P's expressions for Maxwell's equations in terms of charges and
> currents are found in Chapter 14. While Jefimenko uses a variety of
> vector identities and deductive reasoning to achieve his results, P&P
> use a bit more straightforward (in my opinion) Fourier transform
> process,
>
>
>
> Their results, after adjusting for nomenclature differences, are
> *identical.*
>
>
>
> But it turns out that P&P were not the first to have these insights.
> Kirk did a little "detective work" and uncovered prior art dating back
> to the30's in the form of a paper by Stratton and Chu (of "Chu limit"
> antenna fame?) that contains one of the two expressions relating E and
> H to currents and charges.
>
>
>
> So.. in introducing "Jefimenko's Equations," did the author simply
> miss prior art. Or did he ignore it?
>
>
>
> We may never know.
Since he died last year, you are probably right about that. But the
references in his 2000 book seem to indicate that he just did not know
about the "prior art".
> But maybe a "hint" is contained ib P&P's rendition of Maxwell's
> equations into Hamiltonians. Prior to doing si, P&P make the following
> pronouncement: In describing the electromagnetic field, (24-3) P&P
> state unequivocally (and without proof) that ".energy oscillates
> between electric and magnetic energy,,,"
>
> Since Jefimenko clearly understood that this was *not* the case im an
> EM wave. it would be logical; (and wntirely human)l for him to not
> cite this work as a reference.
If he had never read it, why would he cite it? :-)
> And this makes the folliowing question perhaps germane: In view of an
> 80+ year history during which it has been understood clearly rhat E
> does not *cause* H and H does not *cause* E, why in the world would
> anyone think that it did!
Apparently it wasn't so clear in that "80+ year history".
> BTW. On another newsgroup, several posters cstegorically ignored
> Jefimenko's propositions regarding Gravitation stating that since
> Jefmenko had not provided a Hamiltonoan "proof" of the hypothesis/,
> Jefimenko's Gravitational Equations - with one minus sugn - have been
> shown to be valid by P&P, shall we consider Jefimenko's Gravitational
> Equations to supercede those of Newton anf Einsteinm?
No. It seems to me that Jefimenko's Gravitational Equations can be
derived from GR.
Best,
Fred Diether
Timo Nieminen
> But it turns out that P&P were not the first to have these insights. Kirk
> did a little "detective work" and uncovered prior art dating back to the30's
> in the form of a paper by Stratton and Chu (of "Chu limit" antenna fame?)
> that contains one of the two expressions relating E and H to currents and
> charges.
I'd say it goes back to L. Lorenz,
L. Lorenz
"Ueber die Identität der Schwingungen des Lichts mit den
elektrischen Strömen"
Annalen der Physik und Chemie 131, 243-263 (1967)
L. Lorenz
"On the identity of the vibrations of light with electrical
currents"
Phil. Mag. 34, 287-301 (1867)
preceding even Maxwell's Treatise. OK, this is in terms of the vector and
scalar potential, so if you want it in terms of fields, you have to
fast-forward to Heaviside. Either way, prior art goes back a long way.
--
Timo
Bill Miller
"FrediFizzx" <fredi...@hotmail.com> wrote in message
news:8c8k6u...@mid.individual.net...
>
> Do you have a reference for your claimed statistics? :-)
Yep... Atleast 50% of the replies on this thread, Namely you -- in spite of
your claim to the contrary.:-)
Please see below.
>Not many
> physicists that I know of think that the E and B fields of EM radiation
> cause each other. Nor do I. But that does not mean in certain
> situations that a B field CAN'T cause an E field. Toss a bar magnet
> thru a loop of wire.
<snip>
Fred, it appears to me that you have fallen for a Freshman Error --
confusing congruence with causality.
Does tossing a magnet through a wire loop demonstrate a causal relationship
between the throwing action and the current induced in the loop? Yes.
Does it show a causal relationship between a changing magnetic field and an
induced E filed. No.
It seems well recognized (sorry, no statistics) that the magnetism in
permanent magnets is comes from electron motion.
Please take a look at Jefimenko's equations and read his explanation of what
is really going on -- as found on Chapter 2, pp 19 - 41 of "Causality,
Electromagnetic Induction and Gravitation." In particular, you will be
interested in section 2-6, Induction by moving magnets.
All the best,
Bill Miller
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8c8k6u...@mid.individual.net...
>>
>> Do you have a reference for your claimed statistics? :-)
>
> Yep... Atleast 50% of the replies on this thread, Namely you -- in
> spite of your claim to the contrary.:-)
Links please or it didn't happen.
>>Not many
>> physicists that I know of think that the E and B fields of EM
>> radiation
>> cause each other. Nor do I. But that does not mean in certain
>> situations that a B field CAN'T cause an E field. Toss a bar magnet
>> thru a loop of wire.
> <snip>
>
> Fred, it appears to me that you have fallen for a Freshman Error --
> confusing congruence with causality.
Trust me; I'm not confused about this at all. It is all about boundary
and initial conditions as to what causes what.
> Does tossing a magnet through a wire loop demonstrate a causal
> relationship between the throwing action and the current induced in
> the loop? Yes.
>
> Does it show a causal relationship between a changing magnetic field
> and an induced E filed. No.
Yes it does.
> It seems well recognized (sorry, no statistics) that the magnetism in
> permanent magnets is comes from electron motion.
We are not concerned with electron motion here. Only that the bar
magnet has a certain B field. This is a classical problem; no need to
interject quantum physics here with electrons. Is an E field produced
somewhere when the B field of the bar magnet goes thru the loop of wire?
> Please take a look at Jefimenko's equations and read his explanation
> of what is really going on -- as found on Chapter 2, pp 19 - 41 of
> "Causality, Electromagnetic Induction and Gravitation." In particular,
> you will be interested in section 2-6, Induction by moving magnets.
LOL! Ya mean where he has tried to disguise a part of a changing
magnetic field by calling it E_k?
E_k = -dA/dt (where the d's are partials) his eq. (2-4.10)
A is basically the irrotational part of a B field. B = curl A
Best,
Fred Diether
p.ki...@ic.ac.uk
> Fred, it appears to me that you have fallen for a Freshman Error --
> confusing congruence with causality.
> Does tossing a magnet through a wire loop demonstrate a causal relationship
> between the throwing action and the current induced in the loop? Yes.
> Does it show a causal relationship between a changing magnetic field and an
> induced E filed. No.
Just out of curiousity, what _would_ you consider a causal relationship
between a changing magnetic field and an induced E field? What would
such a mathematical expression look like?
Also, what definition of causality are you using? Kramers Kronig,
or something else?
--
---------------------------------+---------------------------------
Dr. Paul Kinsler
Blackett Laboratory (Photonics) (ph) +44-20-759-47734 (fax) 47714
Imperial College London, Dr.Paul...@physics.org
SW7 2AZ, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/
blackhead
> Jefiimenko's Equations show the relationship between E Fields, H Fields,
> charge density and current. These equations show that it is not possible for
> an E field to *cause* an H field and vice versa. Wikipedia's link is:
>
> http://en.wikipedia.org/wiki/Jefimenko%27s_equations
>
> In spite of this evidence, it appears to me that most of the Electrical
> Engineering community
Yes, because electrical engineering courses tend to be more pragmatic
when it comes to teaching electromagnetic theory. A changing magnetic
field causes an induced emf is a useful concept when designing
transformers, inductors, generators, motors etc.
>as well as much of the Electromagnetic Physics
I'd say no. Physics courses are more concenrned about the fundamental
principles and so will teach a relativistic approach that makes it
obvious the E and B fields are part of the electromagnetic field,
neither causing the other. This has been known since 1905 and 1907 at
least with the papers of Einstein and Minkowski.
As a guess, I'd say you're an electrical engineer who's unaware of
just how far physics has progressed since Faraday and Maxwell. Take a
look at the relativity section in Griffiths's Electrodyanmics book for
physics undergraduates.
FrediFizzx
Well... after thinking about this more, E_k = -dA/dt is basically the same
as curl E = -dB/dt.
curl E(A,t) = - d(curl A)/dt
So I guess what we have here is that a changing A field would produce his
E_k. A part of an E field?
Best,
Fred Diether
Bill Miller
<snip>> Well... after thinking about this more, E_k = -dA/dt is basically
> as curl E = -dB/dt.
>
> curl E(A,t) = - d(curl A)/dt
>
> So I guess what we have here is that a changing A field would produce his
> E_k. A part of an E field?
Yep. This is covered on pp30 and 31. He coins the term, electrokinetic
impulse for the integral of E_k. He points out that -- unlike A -- this
"impulse" is a measurable item and thus provides an operational definition
and a physical interpretation of a (hitherto) theoretical item: magnetic
vector potential.
More on your previous comments later.
All the best,
Bill
>
> Best,
>
> Fred Diether
>
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8cg7au...@mid.individual.net...
> <snip>> Well... after thinking about this more, E_k = -dA/dt is
> basically the same
>> as curl E = -dB/dt.
>>
>> curl E(A,t) = - d(curl A)/dt
>>
>> So I guess what we have here is that a changing A field would produce
>> his E_k. A part of an E field?
>
> Yep. This is covered on pp30 and 31. He coins the term, electrokinetic
> impulse for the integral of E_k. He points out that -- unlike A --
> this "impulse" is a measurable item and thus provides an operational
> definition and a physical interpretation of a (hitherto) theoretical
> item: magnetic
> vector potential.
The magnetic vector potential is no longer theoretical since quantum
physics requires it. Where does he say E_k is measurable. I missed it.
Does he say how to measure it?
> More on your previous comments later.
All you need to do is simply answer the question; Is an E field produced
somewhere when the B field of the bar magnet goes thru the wire loop?
Best,
Fred Diether
Bill Miller
<snip>
> The magnetic vector potential is no longer theoretical since quantum
> physics requires it. Where does he say E_k is measurable. I missed it.
> Does he say how to measure it?
Page 30. Right after equation 2-4.4
He does not state how it might be measured.
>
>> More on your previous comments later.
>
> All you need to do is simply answer the question; Is an E field produced
> somewhere when the B field of the bar magnet goes >thru the wire loop?
I believe you are connecting doys that are not there when you assume that
*only* a B field is present in a permanent magnet and that therefore this is
what is causing the E field.
Here are two thoughts. First, you said earlier that you did not accept the
idea of E to H to E exchange in an EM wave. In your next sentence, you toss
a magnet through a loop. These are at odds since, if you are correct about
the magnet, then tossing it through the loop injects an impulse into the
loop. The loop *will* radiate (albeit) briefly. So you can start an EM wave
with a magnetic impulse, but cannot sustain it? How can this be?
Second, let's think about permasnent magnets. Our understanding is that
electron motion generates magnetic dipoles that generate magnetic fields
So, how can moving electrons not contain *any* E field in a microscopic
analysis, but suddenly (?) acquire E fields as the size of the current
increases?
Bill Miller
"blackhead" <larry...@softhome.net> wrote in message
news:c00c2ea8-660d-4601...@l20g2000yqm.googlegroups.com...
> On 8 Aug, 06:41, "Bill Miller" <kt...@yahoo.com> wrote:
>> Jefiimenko's Equations show the relationship between E Fields, H Fields,
>> charge density and current. These equations show that it is not possible
>> for
>> an E field to *cause* an H field and vice versa. Wikipedia's link is:
>>
>> http://en.wikipedia.org/wiki/Jefimenko%27s_equations
>>
>> In spite of this evidence, it appears to me that most of the Electrical
>> Engineering community
>
> Yes, because electrical engineering courses tend to be more pragmatic
> when it comes to teaching electromagnetic theory. A changing magnetic
> field causes an induced emf is a useful concept when designing
> transformers, inductors, generators, motors etc.
Yep. But convenient is not the same as accurate. And the consequences can be
expensive. The EH and CFA antennas were conceived and designed by both EE
and PhD physics types. The original idea was to take advantage of the E to H
to E exchange in a physically compact structure. Literally millions of
dollars and countless man-hours were wasted.
Nevertheless, on another forum dedicated to antenna design and theory, I
have received numerous posting signed by folks with PhD's and EEs. Usually
the post starts with "I teach/used to teach EM in (Insert Name Here)
University and you are dead wrong." Followed by a rote description of how E
causes H causes E, citing Maxwell and always including the tossing of a
magnet through a coil.
Statistically valid? No.
But enough to convince me that what I said is not false.
Thank you for the suggestion.
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8chi0o...@mid.individual.net...
> <snip>
>> The magnetic vector potential is no longer theoretical since quantum
>> physics requires it. Where does he say E_k is measurable. I missed
>> it. Does he say how to measure it?
>
> Page 30. Right after equation 2-4.4
>
> He does not state how it might be measured.
He is talking about A* not E_k.
>>> More on your previous comments later.
>>
>> All you need to do is simply answer the question; Is an E field
>> produced somewhere when the B field of the bar magnet goes >thru the
>> wire loop?
>
> I believe you are connecting doys that are not there when you assume
> that *only* a B field is present in a permanent magnet and that
> therefore this is what is causing the E field.
What other *macroscopic* fields are there for a bar magnet? We are not
concerned with microscopic details for this. All we can measure for the
bar magnet is its B field.
> Here are two thoughts. First, you said earlier that you did not accept
> the idea of E to H to E exchange in an EM wave. In your next sentence,
> you toss a magnet through a loop. These are at odds since, if you are
> correct about the magnet, then tossing it through the loop injects an
> impulse into the loop. The loop *will* radiate (albeit) briefly. So
> you can start an EM wave with a magnetic impulse, but cannot sustain
> it? How can this be?
Not at odds; you can sustain it by oscillating the bar magnet thru the
loop.
> Second, let's think about permasnent magnets. Our understanding is
> that electron motion generates magnetic dipoles that generate magnetic
> fields So, how can moving electrons not contain *any* E field in a
> microscopic analysis, but suddenly (?) acquire E fields as the size of
> the current increases?
Not sure why you want to keep dragging quantum physics into a purely
classical description of a physical process but your description of the
microscopic details is not accurate. All we know is that the bar magnet
has a B field and no E fields macroscopically. Same thing with an
electromagnet where you have a DC current flowing.
The point of all this is that Jefimenko is not entirely right about
"causes" *macroscopically*. A changing B field can "cause" an E field
even though that is not the case in/for EM radiation in free space. The
E and B fields in EM radiation don't cause each other. In the case
above they were caused by whole apparatus simultaneously. Ya have to
see here that it is all about boundary and initial conditions. His
presentation in section 2.6 is more about microscopic details of a
magnet so it is out of the realm of classical EM though it is possibly a
neat bridge to a more quantum description of the process.
Best,
Fred Diether
Benj
> The point of all this is that Jefimenko is not entirely right about
> "causes" *macroscopically*. A changing B field can "cause" an E field
> even though that is not the case in/for EM radiation in free space. The
> E and B fields in EM radiation don't cause each other. In the case
> above they were caused by whole apparatus simultaneously. Ya have to
> see here that it is all about boundary and initial conditions. His
> presentation in section 2.6 is more about microscopic details of a
> magnet so it is out of the realm of classical EM though it is possibly a
> neat bridge to a more quantum description of the process.
Words, words, words, and more words. You can't TALK your way out of
this. If you want to challenge Jefimenko you'll have to challenge his
derivation of his "causal" equations for B and E. Clearly both are
CAUSED ONLY by charges and currents and their rates of change. Hence
charge (whatever that is) is the causal source here! The causal
equation for B does not include E as a variable and the causal
equation for E does not include B as a variable. That does NOT say
that E and B cannot be related. In fact, we know they ARE related. The
real question is are they related causally.
So if you wish to challenge these equations then please show us the
exact point in Jefimenko's derivation of them where he made his
mistake! That we will accept as proof. (and will evaluate
accordingly) Anything else is hand-waving.
Benj
> "Bill Miller" <kt...@yahoo.com> wrote in message
> > Fred, it appears to me that you have fallen for a Freshman Error --
> > confusing congruence with causality.
Yes he has, but FreddiFizzle falls for lots of mistakes.
> Trust me; I'm not confused about this at all. It is all about boundary
> and initial conditions as to what causes what.
>
> > Does tossing a magnet through a wire loop demonstrate a causal
> > relationship between the throwing action and the current induced in
> > the loop? Yes.
>
> > Does it show a causal relationship between a changing magnetic field
> > and an induced E filed. No.
>
> Yes it does.
Oh here we go! "Proof by assertion" That one gets me every time!
Anyone falling for the B and E cause each other falls for basic
Freshman-like mathematical mistakes. Causality requires retardation.
Things happening at the same time are NOT causal. Hence to examine
causality one must look carefully at retardation. But NOBODY wants to
bother with that because it's a complication. It's so much easier to
simply use simplified but WRONG equations! So we have the "standard"
proof used by nearly everyone that one can simply look at Maxwell's
equations and see that a changing B causes an E field. But the
freshman mistake is that in those equations B and E are NOT delayed
from each other. Hence, while the equation might be TRUE, it can't be
causal. It's as simple as that. FreddiFIzzle here is trying to cover
his freshman math mistake with bluster.
Bottom line here. is that Bill is correct and Freddi is totally wrong
(even by assertion). What happens if you toss a magnet through a
coil? Well Freddi thinks that the magnet creates a magnetic field that
changes and hence creates an E field in the wire. But the reality is
rather different. What is actually happening is that a magnet is
believed to consist of circulating currents. When one tosses a magnet,
those currents (made up of charges) become charges in motion! Hence
the true relationship is between the motion of charges and the
generation of an E field at a distance. The B field of the magnet
travels away from those currents at the same speed as the generated E
field. Hence B and E are related but B and E happen at the same time.
That is PROOF they are not causing each other.
This misconception, while not universal in physics certainly is
pervasive. I tried unsuccessfully to convince the Wikipedia staff to
remove this error from their article on EM waves. The problem seems
to be that Maxwells equations make the relationship between E and B
seem to obvious that nobody ever bothers to understand that there is a
difference between "equals" and "causes".
FrediFizzx
> The point of all this is that Jefimenko is not entirely right about
> "causes" *macroscopically*. A changing B field can "cause" an E field
> even though that is not the case in/for EM radiation in free space.
> The E and B fields in EM radiation don't cause each other. In the
> case above they were caused by whole apparatus simultaneously. Ya
> have to see here that it is all about boundary and initial conditions.
> His presentation in section 2.6 is more about microscopic details of a
> magnet so it is out of the realm of classical EM though it is possibly
> a neat bridge to a more quantum description of the process.
Perhaps the best thing here would be an attempt to explain in the case
of the magnet and wire loop a changing B field can cause an E field so
why doesn't that happen in the case of EM radiation in free space? Why
doesn't their "changing" fields cause each other? The simple answer is
because the fields aren't changing relative to each other. Ride the
crest of the wave. :-) Nothing is changing. For a deeper answer, I
would have to resort to the quantum "vacuum" as a relativistic medium.
We probably shouldn't go there... yet. ;-)
Best,
Fred Diether
FrediFizzx
news:7f817268-a5a3-49a4...@s9g2000yqd.googlegroups.com...
> On Aug 12, 9:54 pm, "FrediFizzx" <fredifi...@hotmail.com> wrote:
>
>> The point of all this is that Jefimenko is not entirely right about
>> "causes" *macroscopically*. A changing B field can "cause" an E
>> field
>> even though that is not the case in/for EM radiation in free space.
>> The
>> E and B fields in EM radiation don't cause each other. In the case
>> above they were caused by whole apparatus simultaneously. Ya have to
>> see here that it is all about boundary and initial conditions. His
>> presentation in section 2.6 is more about microscopic details of a
>> magnet so it is out of the realm of classical EM though it is
>> possibly a
>> neat bridge to a more quantum description of the process.
>
> Words, words, words, and more words. You can't TALK your way out of
> this.
Sorry Benj, this whole discussion seems to be way over your
comprehension level. Or are you just having a brain-fart tonight?
> If you want to challenge Jefimenko you'll have to challenge his
> derivation of his "causal" equations for B and E. Clearly both are
> CAUSED ONLY by charges and currents and their rates of change. Hence
> charge (whatever that is) is the causal source here! The causal
> equation for B does not include E as a variable and the causal
> equation for E does not include B as a variable. That does NOT say
> that E and B cannot be related. In fact, we know they ARE related. The
> real question is are they related causally.
>
> So if you wish to challenge these equations then please show us the
> exact point in Jefimenko's derivation of them where he made his
> mistake! That we will accept as proof. (and will evaluate
> accordingly) Anything else is hand-waving.
Why would I want to challenge Jefimenko's causal equations for B and E?
They are exactly right. As I said above, you seem to be missing the
whole point of this discussion. Please pay better attention.
Best,
Fred Diether
p.ki...@ic.ac.uk
> Words, words, words, and more words. You can't TALK your way out of
> this.
Well indeed. So let me hijack your comment as an excuse to re-pose the
questions I asked elsewhere in this thread (for you all to answer):
1) What would you consider a causal relationship between a changing
magnetic field and an induced E field? What would its mathematical
expression look like? (I don't care if its "wrong" or disagrees with
EM -- I just want to know what you _might_ consider causal).
2) What definition of causality are you using? And what does its
mathematical implementation look like? Do you follow Kramers Kronig
as is popular in EM, or something else?
Since I generally follow Kramers Kronig, I consider equations like
dA/dt = B
to express a causal relationship: i.e. that B causes changes in A.
PS: and if you really want to pick holes in EM, try this:
http://syrte.obspm.fr/~coll/Papers/Electromagnetism/ConceptsElectroM.pdf
Bill Miller
<p.ki...@ic.ac.uk> wrote in message
news:gjrfj7-...@ph-kinsle.qols.ph.ic.ac.uk...
<snip>
>
> Since I generally follow Kramers Kronig, I consider equations like
>
> dA/dt = B
>
> to express a causal relationship: i.e. that B causes changes in A.
How in the world can you say this when A and B are occurring at the same
time? Maybe you live in a world where a causal event doesn't necessarily
happen *before* the caused event.
But I've never been in that world.
Truly causal equations must, in my NTBHO, include retardation. If they don't
deal with the real world phenomenon that a cause *must* precede the effect,
then they cannot be causal.
All the best,
Bill Miller
>
Bill Miller
>> <snip>
> He is talking about A* not E_k.
OK. And A* is not related to A? I think we understand this, and suggest that
we eschew obfuscation. :-)
>
>>>> More on your previous comments later.
>>>
>>> All you need to do is simply answer the question; Is an E field produced
>>> somewhere when the B field of the bar magnet goes >thru the wire loop?
>>
>> I believe you are connecting doys that are not there when you assume that
>> *only* a B field is present in a permanent magnet and that therefore this
>> is what is causing the E field.
>
> What other *macroscopic* fields are there for a bar magnet?
This is where you are missing the point. The macroscopic field that is
present is E_k. It is that field, and not the magnetic field, that is
responsible for induction.
If you disgree with Jefimenko's hypothesis and proof, then please review his
work and identify where he has made the "fatal flaw(s)" that render his
conclusions invalid.
We are not
> concerned with microscopic details for this. All we can measure for the
> bar magnet is its B field.
Yep. Lay a bar magnet on the table. Measure it, All you find is the B field.
Hmmm... I wonder what happens if you move it.
Gee... the moving magnet induces a current in a nearby loop. I wonder if
that might be what Jefimenko found the E_k field. E_k is shorthand for
Electrokinetic field. He named it that way because it only manifests itself
when under motion.
I wonder if that might be why, when we measure a stationary bar magnet, we
don't see it?
>
> Not at odds; you can sustain it by oscillating the bar magnet thru the
> loop.
Not at all necessary. The impulse contains the makings of an EM field and --
according to you -- the B field caused it.
Not the E_k field.
And you are certain of that, even though Jefimenko (and it appears, many
others) have shown that *the* complete description of an E field contains no
references to a B field, and *the* complete description of a B field
contains no references to an E field.
That's not science. That's dogma.
Benj
> Well indeed. So let me hijack your comment as an excuse to re-pose the
> questions I asked elsewhere in this thread (for you all to answer):
OK.
> 1) What would you consider a causal relationship between a changing
> magnetic field and an induced E field? What would its mathematical
> expression look like? (I don't care if its "wrong" or disagrees with
> EM -- I just want to know what you _might_ consider causal).
A typical example of such a thing would be the way the current and
voltage behave in resonant circuits. You would note that in that case
one lags the other by 90 degrees. Oddly there is a great tendency to
apply this reasoning to EM waves and assume that B and E are likewise
90 degrees out of phase there which explains E-B causality correctly.
Unfortunately this wonderful and correct explanation has no connection
with reality whatsoever given that E and B are in phase in EM waves.!
> 2) What definition of causality are you using? And what does its
> mathematical implementation look like? Do you follow Kramers Kronig
> as is popular in EM, or something else?
Well, Kramers Kronig is of course a MATHEMATICAL implementation of
complex variables at that. So right off the bat we are dealing with
"imaginary" quantities. But be that as it may, IF you are willing to
accept a complex variable representation of EM quantities and IF you
are willing to throw out all "non-physical" quantities, one does
arrive at a causality similar to others. Namely that things can not
happen before the driving force is applied.
Now I've suggested that Jefimenko's derivation be questioned if one
wants to question his assertions. One such questioning (since nobody
else has done it, I will) is that Jefimenko asserts that not only does
causality demand that an action precede the effect (which everyone
agrees with) he also asserts that it means that they also cannot
happen at the same place at the same time or causality is violated.
You can see the problem here. if the cause and effect are at the same
point, retardation is zero. Hence the usual arguments get fuzzy. As
far as I know Jefimenko never justifies his assertion about
simultaneous events at the same point. I would suggest based on Kramer
Kronig that the only way such a causality could occur would be if the
"applied action" were of an impulse nature! A Dirac Delta function
can indeed produce simultaneous cause and effect at a single point.
But I hope we are all remembering here that mathematics is NOT more
real than reality? As you know such an action implies an INFINITE
driving force for ZERO time which is CLEARLY a non-physical concept
that cannot exist in reality. Hence Jefimenko's assertion shows up as
true that two simultaneous things, even occurring at the same
location, violates causality, unless the existence of infinite zero-
time driving functions can be demonstrated. Please note that in
mathematics there is NO requirement of justifying ANY construct beyond
self-consistency in your mathematical system.
> Since I generally follow Kramers Kronig, I consider equations like
>
> dA/dt = B
>
> to express a causal relationship: i.e. that B causes changes in A.
A and B occur at the SAME time which makes the relationship non-causal
for A and B located at any two different points in space! And by the
above discussion it is clear that even if A and B are at the SAME
single point in space they can cannot be causal! The equation,
however, is also true! The mistake is regarding one side of the
equation as CAUSING the other side. It doesn't say that. It only says
they are equal! IF we accept Jefimenko's causal equations, it is
clear that the source of both A and B are currents and their changes.
BOTH A and B travel outward from the source current and are both
retarded! Indeed in vacuum they are both retarded by the same amount
and hence simultaneous! At that point all arguments denying causality
between A and B apply.
> PS: and if you really want to pick holes in EM, try this:
> http://syrte.obspm.fr/~coll/Papers/Electromagnetism/ConceptsElectroM.pdf
Quit trying to change the subject! While it is true that
Electromagnetics having been around little changed since the time of
Maxwell are LONG overdue for a careful and critical review, [A process
toward which Jefimenko and others have taken a very good first step!]
the subject here is electromagnetic causality.
Cheers.
p.ki...@ic.ac.uk
> Truly causal equations must, in my NTBHO, include retardation. If they don't
> deal with the real world phenomenon that a cause *must* precede the effect,
> then they cannot be causal.
Then tell me what your preferred definition looks like mathematically -
i.e. Put up or shut up.
p.ki...@ic.ac.uk
> > 1) What would you consider a causal relationship between a changing
> > ? ?expression look like? (I don't care if its "wrong" or disagrees with
> > ? ?EM -- I just want to know what you _might_ consider causal).
> A typical example of such a thing [...]
"Words, words, words, and more words". Why not just answer the question?
Benj
> Bill Miller <kt...@yahoo.com> wrote:
> > Truly causal equations must, in my NTBHO, include retardation. If they don't
> > deal with the real world phenomenon that a cause *must* precede the effect,
> > then they cannot be causal.
>
> Then tell me what your preferred definition looks like mathematically -
> i.e. Put up or shut up.
So your position is that mathematics is more real than reality?
Nice dream world, but don't call yourself a scientist. Tell them you
are a mathematician.
Benj
> Benj <bjac...@iwaynet.net> wrote:
> > > 1) What would you consider a causal relationship between a changing
> > > ? ?magnetic field and an induced E field? What would its mathematical
> > > ? ?expression look like? (I don't care if its "wrong" or disagrees with
> > > ? ?EM -- I just want to know what you _might_ consider causal).
> > A typical example of such a thing [...]
>
> "Words, words, words, and more words". Why not just answer the question?
I did. Why not learn to read with some comprehension?
The energy flows back and forth between B and E causally in resonant
circuits. (or for different quantities in pendulums etc.) If you can
only understand it mathematical language, there are many elementary
texts that will derive it for you. I'm not here to spoon-feed you.
Idiot.
blackhead
I think Faraday's law is an example of the third cause fallacy which
concludes that A causes B when they're both caused by C. i.e a
changing B causes a changing E when they're both caused by a changing
current elsewhere.
Is it worth replacing the B for J in the mathematical expression for
Faraday's law to make causality clear?
I think it must have been debated in the past already, with some good
reason for sticking with B. The most obvious is that with J, you would
have to introduce an additional constant into the expression that
depends upon the circuit geometry, whereas B implicitly contains it.
On the other hand, it leads to the more thoughtful struggling with an
incorrect interpretation of what's really going on in Faraday's law.
Regards, Larry.
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8cjmvc...@mid.individual.net...
>>> <snip>
>> He is talking about A* not E_k.
>
> OK. And A* is not related to A? I think we understand this, and suggest
> that we eschew obfuscation. :-)
OK, plus thanks to Benj, we have some added "noise" in this conversation
now. ;-)
>>>>> More on your previous comments later.
>>>>
>>>> All you need to do is simply answer the question; Is an E field
>>>> produced somewhere when the B field of the bar magnet goes >thru the
>>>> wire loop?
>>>
>>> I believe you are connecting doys that are not there when you assume
>>> that *only* a B field is present in a permanent magnet and that
>>> therefore this is what is causing the E field.
>>
>> What other *macroscopic* fields are there for a bar magnet?
>
> This is where you are missing the point. The macroscopic field that is
> present is E_k. It is that field, and not the magnetic field, that is
> responsible for induction.
>
> If you disgree with Jefimenko's hypothesis and proof, then please review
> his work and identify where he has made the "fatal flaw(s)" that render
> his conclusions invalid.
I don't know why you think there is some "proof"? There is no proof for E_k
until someone figures out how to measure it.
> We are not
>> concerned with microscopic details for this. All we can measure for the
>> bar magnet is its B field.
>
> Yep. Lay a bar magnet on the table. Measure it, All you find is the B
> field. Hmmm... I wonder what happens if you move it.
You find a changing B field and nothing else. Very simple.
> Gee... the moving magnet induces a current in a nearby loop. I wonder if
> that might be what Jefimenko found the E_k field. E_k is shorthand for
> Electrokinetic field. He named it that way because it only manifests
> itself when under motion.
>
> I wonder if that might be why, when we measure a stationary bar magnet, we
> don't see it?
No one has figured out how to measure it if it does in fact exist.
>> Not at odds; you can sustain it by oscillating the bar magnet thru the
>> loop.
>
> Not at all necessary. The impulse contains the makings of an EM field
> and -- according to you -- the B field caused it.
>
> Not the E_k field.
*Changing* B field caused it along with the proper setup (boundary and
initial conditions). Until someone can measure his E_k, it is purely
theoretical.
> And you are certain of that, even though Jefimenko (and it appears, many
> others) have shown that *the* complete description of an E field contains
> no references to a B field, and *the* complete description of a B field
> contains no references to an E field.
Sorry, but the Maxwell equations do show the relationship between E and B
fields. And there is no reason why you can't insert Jefimenko's causal
equations for E and B into,
curl E = -dB/dt
and
curl B = mu0 J + dE/(c^2 dt)
If you think Maxwell's equations are not valid, show us and then go to
Stockholm to collect your prize. :-)
Best,
Fred Diether
FrediFizzx
> I think Faraday's law is an example of the third cause fallacy which
> concludes that A causes B when they're both caused by C. i.e a
> changing B causes a changing E when they're both caused by a changing
> current elsewhere.
>
> Is it worth replacing the B for J in the mathematical expression for
> Faraday's law to make causality clear?
Well... there is no reason why you can't insert Jefimenko's causal
equation for B into curl E = -dB/dt. You can if you wish to. But you
don't need to if you know what the value for B is.
Best,
Fred Diether
FrediFizzx
news:tq9gj7-...@ph-kinsle.qols.ph.ic.ac.uk...
> Bill Miller <kt...@yahoo.com> wrote:
>> Truly causal equations must, in my NTBHO, include retardation. If
>> they don't
>> deal with the real world phenomenon that a cause *must* precede the
>> effect,
>> then they cannot be causal.
>
> Then tell me what your preferred definition looks like
> mathematically -
> i.e. Put up or shut up.
Well.. I think Bill did already at the beginning of this thread.
http://en.wikipedia.org/wiki/Jefimenko%27s_equations
At least a definition of causal equations for E and B fields. Should
give you some sense of what he is looking for as far as "causal" goes.
Of course the discussion that goes with those equations looks to be a
bit misleading.
Best,
Fred Diether
p.ki...@ic.ac.uk
If I want useful models of reality, I need maths to add rigour to
the physical concepts. I thought maybe you and/or Bill might have
had some interesting ideas about causality. But if you can't make
them precise, then how can I tell?
Benj
> I think Faraday's law is an example of the third cause fallacy which
> concludes that A causes B when they're both caused by C. i.e a
> changing B causes a changing E when they're both caused by a changing
> current elsewhere.
>
> Is it worth replacing the B for J in the mathematical expression for
> Faraday's law to make causality clear?
>
> I think it must have been debated in the past already, with some good
> reason for sticking with B. The most obvious is that with J, you would
> have to introduce an additional constant into the expression that
> depends upon the circuit geometry, whereas B implicitly contains it.
> On the other hand, it leads to the more thoughtful struggling with an
> incorrect interpretation of what's really going on in Faraday's law.
You have, of course, placed your finger squarely upon the problem!
There is no question that an induced E field can be calculated
(Maxwell said "measured by") from the values of a changing magnetic
field. It's a "Law". Faraday's Law, in fact. It works. It's useful.
Everybody is happy... until someone like Bill or I begin to assert
that an induced E field is NOT caused by a changing magnetic field.
The problem is typically human. Back in the past someone derived as
you did that there is no reason to stick with J (and let me note that
Faraday himself pointed out the causality was with J and not B!)
because B implicitly contains the effects from J. The assumption
(always a mistake with humans) was that the interested calculator
would remember that the causality was from J and not B, while using B
to get an answer. And typically, everyone was so happy with the
results of the "shortcut" that they forgot it's origins.
And that's when science becomes dogma. Everybody was supposed to
REMEMBER that J is the cause, but having forgotten it, Faraday's law
is chanted as dogma without proof.
Think about it. How can B in the center of a loop induce a current in
that loop it is not even touching? What is the mechanism? How can an E
field be induced in a region where there is not even a B field
(outside a long solenoid or toroid)? One mistake leads to others
which are then attempted to be covered up with bluster. It's only
human!
Benj
> OK, plus thanks to Benj, we have some added "noise" in this conversation
> now. ;-)
Glad I could help, Fred!
Hey it's a nasty job, but with Uncle Al gone, SOMEONE has to do it!
Benj
blackhead
> > confusing congruence with causality.
> > between the throwing action and the current induced in the loop? Yes.
> > induced E filed. No.
>
> Just out of curiousity, what _would_ you consider a causal relationship
> between a changing magnetic field and an induced E field? What would
> such a mathematical expression look like?
I was hoping Bill would answer this for himself here. Essentially, he
wants to replace the Maxwell's equations that contain an E one one
side, B on the other with rho, j, dj/dt on the rhs. This then make
clear that E and B are caused by charge densities and their time
variation, rather than by one another.
> Also, what definition of causality are you using? Kramers Kronig,
> or something else?
>
> --
> ---------------------------------+---------------------------------
> Dr. Paul Kinsler
> Blackett Laboratory (Photonics) (ph) +44-20-759-47734 (fax) 47714
> Imperial College London, Dr.Paul.Kins...@physics.org
Szczepan Bialek
"Benj" <bja...@iwaynet.net>wrote
news:9e1a2745-329b-4a05...@c10g2000yqi.googlegroups.com...
>
>Think about it. How can B in the center of a loop induce a current in
that loop it is not even touching? What is the mechanism? How can an E
field be induced in a region where there is not even a B field
(outside a long solenoid or toroid)? One mistake leads to others
which are then attempted to be covered up with bluster. It's only
human!
The first mistake was made by Heaviside:
"Another question, somewhat connected, is contained in Prof. Poynting's
suggestion (in letter to Prof. Lodge, The Electrician, p. 829, vol. xxi.)
that electric displacement may possibly be produced without magnetic force
by the agency of pyroelectricity. But, whatever the agency, it would, I
conceive, be a new fact quite outside Maxwell's theory legitimately
developed. We may have subsidence of electric displacement without magnetic
force; but I cannot see any way to produce it."
From:
http://en.wikisource.org/wiki/Electromagnetic_effects_of_a_moving_charge
S*
glen herrmannsfeldt
(snip)
>>Think about it. How can B in the center of a loop induce a current in
> that loop it is not even touching? What is the mechanism? How can an E
> field be induced in a region where there is not even a B field
> (outside a long solenoid or toroid)? One mistake leads to others
> which are then attempted to be covered up with bluster. It's only
> human!
Don't forget the Aharanov-Bohm effect.
-- glen
ji...@specsol.spam.sux.com
over a hundred years ago.
News flash bozo, a lot has happened in a hundred years.
--
Jim Pennino
Remove .spam.sux to reply.
FrediFizzx
> On 11 Aug, 13:27, p.kins...@ic.ac.uk wrote:
>> Bill Miller <kt...@yahoo.com> wrote:
>> > Fred, it appears to me that you have fallen for a Freshman Error --
>> > confusing congruence with causality.
>> > Does tossing a magnet through a wire loop demonstrate a causal
>> > relationship
>> > between the throwing action and the current induced in the loop?
>> > Yes.
>> > Does it show a causal relationship between a changing magnetic
>> > field and an
>> > induced E filed. No.
>>
>> Just out of curiousity, what _would_ you consider a causal
>> relationship
>> between a changing magnetic field and an induced E field? What would
>> such a mathematical expression look like?
>
> I was hoping Bill would answer this for himself here. Essentially, he
> wants to replace the Maxwell's equations that contain an E one one
> side, B on the other with rho, j, dj/dt on the rhs. This then make
> clear that E and B are caused by charge densities and their time
> variation, rather than by one another.
As I said already in this thread, there is no problem inserting
Jefimenko's causal expression for B into Faraday's law. But that
doesn't change that fact that if one wishes to do so, they can just
simplify the process and say that a changing B field causes an E field.
On this point, Jefimenko is a bit misleading in what he says in his
book. Yes, we all know that all *macroscopic* electromagnetic effects
are caused by charged particle motion ultimately. Jefimenko's
hypothetical E_k field to explain induction also looks to me to be more
like a changing part of a magnetic field than an E field. I think he
could have called it B_k rather than E_k. So I think he added more
confusion there.
Best,
Fred Diether
FrediFizzx
> On Aug 13, 6:27 pm, blackhead <larryhar...@softhome.net> wrote:
>
>> I think Faraday's law is an example of the third cause fallacy which
>> concludes that A causes B when they're both caused by C. i.e a
>> changing B causes a changing E when they're both caused by a changing
>> current elsewhere.
>>
>> Is it worth replacing the B for J in the mathematical expression for
>> Faraday's law to make causality clear?
>>
>> I think it must have been debated in the past already, with some good
>> reason for sticking with B. The most obvious is that with J, you
>> would
>> have to introduce an additional constant into the expression that
>> depends upon the circuit geometry, whereas B implicitly contains it.
>> On the other hand, it leads to the more thoughtful struggling with an
>> incorrect interpretation of what's really going on in Faraday's law.
>
> You have, of course, placed your finger squarely upon the problem!
> There is no question that an induced E field can be calculated
> (Maxwell said "measured by") from the values of a changing magnetic
> field. It's a "Law". Faraday's Law, in fact. It works. It's useful.
> Everybody is happy... until someone like Bill or I begin to assert
> that an induced E field is NOT caused by a changing magnetic field.
Insert Jefimenko's causal equation for B into Faraday's law. Now, what
do you have? You have a causal explanation for curl E. But that
doesn't stop us from just replacing (simplifying) that whole expression
by B and saying that a changing B field causes curl E with the right
experimental setup. Mathematics works both ways.
> The problem is typically human. Back in the past someone derived as
> you did that there is no reason to stick with J (and let me note that
> Faraday himself pointed out the causality was with J and not B!)
> because B implicitly contains the effects from J. The assumption
> (always a mistake with humans) was that the interested calculator
> would remember that the causality was from J and not B, while using B
> to get an answer. And typically, everyone was so happy with the
> results of the "shortcut" that they forgot it's origins.
I suspect it is only you that is being "fooled" here. :-)
> And that's when science becomes dogma. Everybody was supposed to
> REMEMBER that J is the cause, but having forgotten it, Faraday's law
> is chanted as dogma without proof.
You really don't understand what Maxwell's equations are all about, do
you?
> Think about it. How can B in the center of a loop induce a current in
> that loop it is not even touching? What is the mechanism? How can an E
> field be induced in a region where there is not even a B field
> (outside a long solenoid or toroid)? One mistake leads to others
> which are then attempted to be covered up with bluster. It's only
> human!
You statement above does not parse.
Best,
Fred Diether
John Polasek
This debate could go on forever in this one-dimensional Gaussian
dreamland bounded on the east by E and on the west by B, while
ignoring D and H. To get right,you simply have to introduce the
coefficients that characterize space, namely e0 and u0. Then you have
to acknowledge the constitutive equations
B = u0H web/m^2 D = e0E coul/m^2 (1)
E and H can very well be primary causes because I know how to make
each one: for E I need a battery and two plates and for H I need a
battery and a coil.
B could never be a cause (but E could) because it has to fall out of
the solution of the differential equations constrained by the boundary
conditions that modulate u0, a mathematically impossible task, while
the construction of a coil to generate H is trivial.
As a simple induction experiment let me turn on H by sending current
through my coil. I can easily vary things to cause dH/dt, and since
the coil is immersed in a medium possessing u0, immediately calculate
or assert
u0dH/dt = dB/dt using (1) H (known) causes B (unknown)
To verify that everything is working, I place a second coil to
surround the B field, and sure enough, I find the terminal voltage
there corresponds to dB/dt and furthermore find it to be proportional
to the number of turns, so I see the voltage building up inch by inch
as I traverse around the turns of the secondary coil.
The E field in fact is a helical object following the turns. Its
calculated curl will be found to be a vector that coincides with the
axis of the coil that originally generated H.
curl E = -dB/dt = -u0dH/dt
These are point functions that are simultaneous and indisputable. Yes
the current was the primary cause for both E and H but only by the
agency of the coil and the fact that the intervening space possesses
u0.
The matter of the current would not even be interesting considering
the other sophisticated consequences, except that in varying the
current I would run into
V = Ldi/dt
finding that I had to buck a back voltage in order to get my current
through.
But all is not lost. I find that my primary voltage V1 is duplicated
by the secondary voltage V2 being related by the nifty ratio N2/N1.
Someone cleverer than I might find a way to make use of that fact.
John Polasek
FrediFizzx
news:3jeg66lfui6pkrso8...@4ax.com...
> On Fri, 13 Aug 2010 18:33:29 -0700, "FrediFizzx"
> <fredi...@hotmail.com> wrote:
>
>>"blackhead" <larry...@softhome.net> wrote in message
>>news:3c173d54-e616-482b...@v41g2000yqv.googlegroups.com...
>>
>>> I think Faraday's law is an example of the third cause fallacy which
>>> concludes that A causes B when they're both caused by C. i.e a
>>> changing B causes a changing E when they're both caused by a
>>> changing
>>> current elsewhere.
>>>
>>> Is it worth replacing the B for J in the mathematical expression for
>>> Faraday's law to make causality clear?
>>
>>Well... there is no reason why you can't insert Jefimenko's causal
>>equation for B into curl E = -dB/dt. You can if you wish to. But you
>>don't need to if you know what the value for B is.
> This debate could go on forever in this one-dimensional Gaussian
> dreamland bounded on the east by E and on the west by B, while
> ignoring D and H.
There is nothing "Gaussian" about this current debate. I do believe we
have been working in SI so far since Bill originally started with,
http://en.wikipedia.org/wiki/Jefimenko's_equations
Which are expressed in SI units. No need to drag your prejudices about
Gaussian units into this discussion.
> To get right,you simply have to introduce the
> coefficients that characterize space, namely e0 and u0.
Sorry, but eps0 and mu0 don't have anything to do with "space". It is
possible they could have something to do with a relativistic quantum
medium that fills space in conjunction with E and B fields (or sources
if you prefer).
> Then you have
> to acknowledge the constitutive equations
> B = u0H web/m^2 D = e0E coul/m^2 (1)
> E and H can very well be primary causes because I know how to make
> each one: for E I need a battery and two plates and for H I need a
> battery and a coil.
For B (or mu0 H), all I need is a bar magnet.
> B could never be a cause (but E could) because it has to fall out of
> the solution of the differential equations constrained by the boundary
> conditions that modulate u0, a mathematically impossible task, while
> the construction of a coil to generate H is trivial.
A changing B of a bar magnet can be a cause. Put the bar magnet in
motion thru a coil of wire.
> As a simple induction experiment let me turn on H by sending current
> through my coil. I can easily vary things to cause dH/dt, and since
> the coil is immersed in a medium possessing u0, immediately calculate
> or assert
> u0dH/dt = dB/dt using (1) H (known) causes B (unknown)
> To verify that everything is working, I place a second coil to
> surround the B field, and sure enough, I find the terminal voltage
> there corresponds to dB/dt and furthermore find it to be proportional
> to the number of turns, so I see the voltage building up inch by inch
> as I traverse around the turns of the secondary coil.
> The E field in fact is a helical object following the turns. Its
> calculated curl will be found to be a vector that coincides with the
> axis of the coil that originally generated H.
> curl E = -dB/dt = -u0dH/dt
All very well known.
Best,
Fred Diether
glen herrmannsfeldt
(snip)
>> To get right,you simply have to introduce the
>> coefficients that characterize space, namely e0 and u0.
> Sorry, but eps0 and mu0 don't have anything to do with "space". It is
> possible they could have something to do with a relativistic quantum
> medium that fills space in conjunction with E and B fields (or sources
> if you prefer).
Some might say that pi is a property of space. (At least one Carl
Sagan book seemed to suggest that.) If so, then 4e-7*pi could also
be a property of space, but more likely just a unit conversion factor.
mu0 and eps0 separately don't have much to do with anything, but
together they do. So, the question left is to use an electrostatic
based unit set, based on the force between two charges, or a magnetic
based unit set based on the force (per unit length) between two
currents. It does seem that electrostatic should be more fundamental,
but MKSA is magnetic based.
-- glen
FrediFizzx
news:i49onr$pl$1...@speranza.aioe.org...
> FrediFizzx <fredi...@hotmail.com> wrote:
> (snip)
>
>>> To get right,you simply have to introduce the
>>> coefficients that characterize space, namely e0 and u0.
>
>> Sorry, but eps0 and mu0 don't have anything to do with "space". It
>> is
>> possible they could have something to do with a relativistic quantum
>> medium that fills space in conjunction with E and B fields (or
>> sources
>> if you prefer).
>
> Some might say that pi is a property of space. (At least one Carl
> Sagan book seemed to suggest that.) If so, then 4e-7*pi could also
> be a property of space, but more likely just a unit conversion factor.
I would say that pi is property of geometrical objects that exist in
space. That may be possible for 4pi*10^-7 also. Problem is that that
number can change just by the redefinition of charge or current. There
is no way of finding out what the "real" values of k_e or k_m should be.
> mu0 and eps0 separately don't have much to do with anything, but
> together they do. So, the question left is to use an electrostatic
> based unit set, based on the force between two charges, or a magnetic
> based unit set based on the force (per unit length) between two
> currents. It does seem that electrostatic should be more fundamental,
> but MKSA is magnetic based.
It really doesn't matter as long as the unit system is self-consistent.
Whether you use charge or current as base units, you will end up with
electric and magnetic proportionality constants like eps0 and mu0 either
way. And as I said above, their values totally depend on how you define
charge or current. So there is nothing special about their present
numerical values but there is something special by the fact that they
appear if charge or current is defined as a base unit.
Best,
Fred Diether
John Polasek
I don't know whether J truly understood those coefficients or not but
I do know that Panofsky Phillips used eps0 freely yet have no idea
how a capacitor works. It is definitely not just two plates with +Q &
-Q and an insulator to keep them apart. At one point he introduces an
infinitesimally thin non-polarizable membrane so the surface charge on
the metal and the surface charge on the dielectric can't touch. The
job of the capacitor is to take voltage across the plates so those
electrodes can fully charge the volume of the dielectric. But there's
not a battery or a volt in the book.
>
>> To get right,you simply have to introduce the
>> coefficients that characterize space, namely e0 and u0.
>
>Sorry, but eps0 and mu0 don't have anything to do with "space". It is
>possible they could have something to do with a relativistic quantum
>medium that fills space in conjunction with E and B fields (or sources
>if you prefer).
As you know Fred since you have my book I have developed a theory of
Pairspace in lurid detail and it is quite equivalent to the quantum
vacuum, with the difference that every detail of Pairspace is
analyzed, while the quantum vacuum is just a good hunch. So let's
just say those qualities exist in the quantum vacuum, a widely
accepted hypothesis.
John Polasek
John Polasek
<fredi...@hotmail.com> wrote:
>"glen herrmannsfeldt" <g...@ugcs.caltech.edu> wrote in message
>news:i49onr$pl$1...@speranza.aioe.org...
>> FrediFizzx <fredi...@hotmail.com> wrote:
>> (snip)
>>
>>>> To get right,you simply have to introduce the
>>>> coefficients that characterize space, namely e0 and u0.
>>
>>> Sorry, but eps0 and mu0 don't have anything to do with "space". It
>>> is
>>> possible they could have something to do with a relativistic quantum
>>> medium that fills space in conjunction with E and B fields (or
>>> sources
>>> if you prefer).
>>
>> Some might say that pi is a property of space. (At least one Carl
>> Sagan book seemed to suggest that.) If so, then 4e-7*pi could also
>> be a property of space, but more likely just a unit conversion factor.
Pi isn't a property of space, but 4pi is: and angle of 4pi radians
encompasses everything in 3-D.
>I would say that pi is property of geometrical objects that exist in
>space. That may be possible for 4pi*10^-7 also.
this instance of 4 pi is a freak-someone was tempted to write that
instead of the number very close to it.
>Problem is that that
>number can change just by the redefinition of charge or current. There
>is no way of finding out what the "real" values of k_e or k_m should be.
It's not the numbers that are important it's the units!
>> mu0 and eps0 separately don't have much to do with anything, but
>> together they do. So, the question left is to use an electrostatic
>> based unit set, based on the force between two charges, or a magnetic
>> based unit set based on the force (per unit length) between two
>> currents. It does seem that electrostatic should be more fundamental,
>> but MKSA is magnetic based.
>
>It really doesn't matter as long as the unit system is self-consistent.
Here is one that is self consistent but devoid of any content:
D = E and B = H
That I believe is your main algebra---yes or no?
Benj
Jefimenko's
> hypothetical E_k field to explain induction also looks to me to be more
> like a changing part of a magnetic field than an E field. I think he
> could have called it B_k rather than E_k. So I think he added more
> confusion there.
Bzzzzt. Wrong Freddi. Jefimenko's E_k field is in fact a REAL honest
to God E field. It does have properties different from an
electrostatic E field, but that is beside the point. And while the E_k
is related to B, is is not a DIRECT, relation. And that is because the
E_k field is measured not by the B field but the FLUX due to the B
field which is quite another thing. Indeed as pointed out E_k can
exist where B is actually Zero. Furthermore the potential created by
changing flux requires a CLOSED PATH to be measured. E_k is a field
with a value at a point. The flux is an integral over an area. Hence,
in fact it DOES NOT relate to an E field at all. It relates to the EMF
around a loop that defines the area of flux integration.
You really need to think about these things.
FrediFizzx
> On Aug 15, 3:11 pm, "FrediFizzx" <fredifi...@hotmail.com> wrote:
> Jefimenko's
>> hypothetical E_k field to explain induction also looks to me to be
>> more
>> like a changing part of a magnetic field than an E field. I think he
>> could have called it B_k rather than E_k. So I think he added more
>> confusion there.
>
> Bzzzzt. Wrong Freddi. Jefimenko's E_k field is in fact a REAL honest
> to God E field.
LOL! Show me where someone has measured this E_k field.
[snip rubbish]
Best,
Fred Diether
Vince Morgan
http://www.freepatentsonline.com/3656013.html might shed some light on the
subject, though I have to admit I'm not sure it is the same thing.
Benj
> > Bzzzzt. Wrong Freddi. Jefimenko's E_k field is in fact a REAL honest
> > to God E field.
>
> LOL! Show me where someone has measured this E_k field.
>
> [snip rubbish]
So you teach that the EMF induced in a wire is produced by... er...
magic?
We haven't even gotten into idiocies like the "one E field" theory and
you are already lost!
Hooper and many others showed that the "one E field" is utter nonsense
and that there are really three E fields based upon the properties of
the fields. And you don't even believe one of them exists?
Idiot.
Bill Miller
>> If you think Maxwell's equations are not valid, show us and then go to
> Stockholm to collect your prize. :-)
C'mon Fred! I have not said that Maxwell's equations are not valid. All I
say is that they are not *causal*
Besides, Stockholm is too cold in the winter, when the prize is given out!
All the best,
Bill Miller
>
> Best,
>
> Fred Diether
>
blackhead
Have any independent institutions carried out tests on Hooper's
claims?
Bill Miller
><snip>> I don't know why you think there is some "proof"? There is no
>
For the sake of what follows, let's assume I agree, and that if a
hypothetical has not been measured, it does not *teally* exist.
>> Yep. Lay a bar magnet on the table. Measure it, All you find is the B
>> field. Hmmm... I wonder what happens if you move it.
>
> You find a changing B field and nothing else. Very simple.
Yep. Unless you move it through a loop, Then you measure an induced current.
Since the only thing you measured (other than the induced current) is a
change in B's position, therefore delta B caused the current.
Huh?
>> Gee... the moving magnet induces a current in a nearby loop. I wonder if
>> that might be what Jefimenko found the E_k field. E_k is shorthand for
>> Electrokinetic field. He named it that way because it only manifests
>> itself when under motion.
>>
>> I wonder if that might be why, when we measure a stationary bar magnet,
>> we don't see it?
>
> No one has figured out how to measure it if it does in fact exist.
Or maybe they *have* measured it and the measurement has been
mis-interpreted ever since Faraday.
>
<snip>
> Sorry, but the Maxwell equations do show the relationship between E and B
> fields. And there is no reason why you can't insert Jefimenko's causal
> equations for E and B into,
>
> curl E = -dB/dt
> and
> curl B = mu0 J + dE/(c^2 dt)
You are tacitly accepting the premise that Maxwell's equations are already
causal since you "know" that delta B cause delta E.
OK
Using your own reasoning that, then curl curl B = mu0 J + dE/(c^2 dt)
*should* also mean that a changing E also causes a delta B.
But, in spite of many attempts to do so, no one has ever succeeded in
neasuring the magnetic field *caused* by delta E. Therefore, by your own
requirement that an entity must be measurable, it would seem that it is you;
not I that is denying Maxwell!
So, what is more pursuasive: An outcome that depends on a mechanism (E_k)
that hasn't been directly measured (or has been measured but
mis-interpreted). OR: an outcome that *should* exist but has not been
measured based on a mechanism (E) that can be measured?
BTW, and to prove that Benj and I are not joined at the hip, I don't
consider you to be an idiot. Instead, it appears to me -- in this narrow
range of inquiry -- you are allowing what you *know* to be true to get in
the way of the critical thinking that I have seen you exercise many many
times.
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8cm0mc...@mid.individual.net...
>><snip>> I don't know why you think there is some "proof"? There is no
>>proof for E_k until someone figures out how to measure it.
>>
>
> For the sake of what follows, let's assume I agree, and that if a
> hypothetical has not been measured, it does not *teally* exist.
No. It could really exist; we just don't know if it does or not. Jefimenko
could be right about E_k but better to not use it for serious evaluation
until we might have at least some kind of validation that it exists.
>>> Yep. Lay a bar magnet on the table. Measure it, All you find is the B
>>> field. Hmmm... I wonder what happens if you move it.
>>
>> You find a changing B field and nothing else. Very simple.
>
> Yep. Unless you move it through a loop, Then you measure an induced
> current. Since the only thing you measured (other than the induced
> current) is a change in B's position, therefore delta B caused the
> current.
You are not just measuring the bar magnet any longer. You have added to the
measurement process.
> Huh?
Huh, what?
>>> Gee... the moving magnet induces a current in a nearby loop. I wonder if
>>> that might be what Jefimenko found the E_k field. E_k is shorthand for
>>> Electrokinetic field. He named it that way because it only manifests
>>> itself when under motion.
>>>
>>> I wonder if that might be why, when we measure a stationary bar magnet,
>>> we don't see it?
>>
>> No one has figured out how to measure it if it does in fact exist.
>
> Or maybe they *have* measured it and the measurement has been
> mis-interpreted ever since Faraday.
I think Jefimenko would have pointed that out in his book. :-)
>> Sorry, but the Maxwell equations do show the relationship between E and B
>> fields. And there is no reason why you can't insert Jefimenko's causal
>> equations for E and B into,
>>
>> curl E = -dB/dt
>> and
>> curl B = mu0 J + dE/(c^2 dt)
>
> You are tacitly accepting the premise that Maxwell's equations are already
> causal since you "know" that delta B cause delta E.
No, this is where the confusion is coming from. They are only causal in
certain situations as in the bar magnet's B field going thru the wire loop.
Most solutions to Maxwell's equations require initial and/or boundary
conditions.
> OK
>
> Using your own reasoning that, then curl curl B = mu0 J + dE/(c^2 dt)
> *should* also mean that a changing E also causes a delta B.
>
> But, in spite of many attempts to do so, no one has ever succeeded in
> neasuring the magnetic field *caused* by delta E. Therefore, by your own
> requirement that an entity must be measurable, it would seem that it is
> you; not I that is denying Maxwell!
No. I have a reference at home that indicates this has probably been
measured. I will try to refind it and sent it later. But this also
requires suitable intial and boundary conditions for a solution. It is easy
to see that since we have a c^2 in the denominator that this dE/(c^2 dt)
effect is going to be very small compared to mu0J.
> So, what is more pursuasive: An outcome that depends on a mechanism (E_k)
> that hasn't been directly measured (or has been measured but
> mis-interpreted). OR: an outcome that *should* exist but has not been
> measured based on a mechanism (E) that can be measured?
As I said in another post, I believe that E_k is more like part of a
magnetic field than an electric field. So the mis-interpretation could be
on Jefimenko's part. He equates it to -dA/dt and to me A is the
irrotational part of a B field.
> BTW, and to prove that Benj and I are not joined at the hip, I don't
> consider you to be an idiot. Instead, it appears to me -- in this narrow
> range of inquiry -- you are allowing what you *know* to be true to get in
> the way of the critical thinking that I have seen you exercise many many
> times.
I think we are having a very good discussion about what Jefimenko says in
his book. Don't get me wrong. Jefimenko *could* be right; the jury is still
out on that so far. What he has said in his book is all very interesting.
I am mainly just playing the devil's advocate here. :-) But I definitely
think he is wrong about what he said that a changing B field *can't* be a
cause. It surely can be a cause with the right setup, *macroscopically*.
We all know microscopically that all of EM comes from charged particles and
their motion.
Benj just has some bug up his butt that he can't seem to get out. LOL! He
tries to understand though. Better than some others.
Best,
Fred Diether
blackhead
I've never understood why people make such a big deal of this effect
on the quantum scale. Some physical property affected by a changing B
where B=0 locally can be observed on a lab bench using a solenoid and
a loop of wire, as suggested by Benj. You can also try passing a
changing current through a loop of hollow conductive tubing and
measuring the voltage across the ends of a loop of wire running inside
it. B=0 inside the tube where the wire is no matter how the current is
changing, yet still there is a volatge across the ends of the loop of
wire.
Is it a retardation effect as expressed in Jefimenko's equations
giving rise to Faraday's induction law?
Is it an example of A being more physical than B?
I think only a relativistic analysis would give an unambiguous
interpretation.
Larry.
> -- glen
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8cm0mc...@mid.individual.net...
>>> If you think Maxwell's equations are not valid, show us and then go
>>> to
>> Stockholm to collect your prize. :-)
>
> C'mon Fred! I have not said that Maxwell's equations are not valid.
> All I say is that they are not *causal*
"And you are certain of that, even though Jefimenko (and it appears,
many
others) have shown that *the* complete description of an E field
contains no
references to a B field, and *the* complete description of a B field
contains no references to an E field."
I suppose I should have asked you what you meant by "*the* complete
descriptions" of E and B fields? I took that as implying you might think
Maxwell's equations may not be valid. But all of classical EM is
contained within them and the solutions to them including Jefimenko's
causal equations. Add the Lorentz force law and then you have
everything you need to solve any classical electrodynamics (CED)
situation. Jefimenko's causal equations are decoupled.
> Besides, Stockholm is too cold in the winter, when the prize is given
> out!
Well, I would go if they ever give me one for Quantum Vacuum Charge. ;-)
But I do hate the cold.
Best,
Fred Diether
Benj
> On 15 Aug, 18:25, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> Is it a retardation effect as expressed in Jefimenko's equations
> giving rise to Faraday's induction law?
Personally I believe this is the case, though it isn't exactly obvious
how this works. I believe that induction relations are a result of a
differential between retarded quantitites. It's interesting that
someone else is making the same guess!
> Is it an example of A being more physical than B?
Obviously A is in a way "more fundamental" than B. One reason being
that as I noted you can create E in regions of zero B. But A on the
other hand, while also retarded, IS present in those zero B regions.
There is plenty of A outside a toroid or solenoid. Hence A easily
provides the needed link in these effects including the Aharanov-
Bohm.
Notice what I already pointed out (and had pooh-poohed). The typical
acausal Maxwell equation links the integral of an E field around a
loop to an integral (of B) over a surface. This is really not what
you want. The kind of relationship that will provide insight links
microscopic elements. For example the Biot-Savart law links B fields
at a point in space to incremental current elements as sources. This
is what you really want. And it turns out in the Jefimenko case, what
happens is you link incremental current elements to A at a point in
space. The rate of change of A creates E_k. Hence this is a much more
pregnant expression than say Faraday's law.
> I think only a relativistic analysis would give an unambiguous
> interpretation.
Call me an optimist, but I really don't believe this. Maxwell's theory
shows much indication of already being relativistic. Hence, My
prediction would be that one day relativity will fall out of Maxwell
rather than the other way round. Jefimenko has already done some
excellent work along these lines. He has for example, showed using
only Maxwells theory, that sticks do not actually get shorter when
traveling at high velocity and there are problems with the slowing of
clock due to velocity as well. He showed that for some
(electromagnetic) clocks velocity slows their readings but for others
this is not the case. Obviously such a contradiction represents
theoretical problems to be dealt with.
Benj
> BTW, and to prove that Benj and I are not joined at the hip, I don't
> consider you to be an idiot. Instead, it appears to me -- in this narrow
> range of inquiry -- you are allowing what you *know* to be true to get in
> the way of the critical thinking that I have seen you exercise many many
> times.
Bill,
Of course I only consider Freddi to be a "rhetorical idiot" rather
than a true one!
But I find it extremely distressing that someone engaged in the
education of the next generation, is so far removed from knowledge of
the scientific method. This is exactly the sort of thinking that got
me banned for life on sci.physics.research and I wasn't even calling
anyone a rhetorical idiot at the time...
Personally I feel it is very important to show "educators" the
disrespect they deserve, because if their smarter students point out
to them the error of their ways, they simply flunk the students and
ruin their future. They can't flunk me, though they can call me
names. Hence I'm speaking on behalf of their smarter students. Sticks
and stones...
FrediFizzx
> On Aug 16, 1:03 am, "FrediFizzx" <fredifi...@hotmail.com> wrote:
>
>> > Bzzzzt. Wrong Freddi. Jefimenko's E_k field is in fact a REAL
>> > honest
>> > to God E field.
>>
>> LOL! Show me where someone has measured this E_k field.
>>
>> [snip rubbish]
>
> So you teach that the EMF induced in a wire is produced by... er...
> magic?
Benj, do yourself a favor and get a copy of Griffiths' "Intro. to
Electrodynamics" and read the chapter on Magnetostatics.
[snip more rubbish]
Best,
Fred Diether
FrediFizzx
Then read Chapter 7 on Electrodynamics.
FrediFizzx
> But I find it extremely distressing that someone engaged in the
> education of the next generation, is so far removed from knowledge of
> the scientific method. This is exactly the sort of thinking that got
> me banned for life on sci.physics.research and I wasn't even calling
> anyone a rhetorical idiot at the time...
Not sure why you think I am some kind of educator; I'm not. Just a
self-study student. There is only one educator that I can think of
right now that frequents this group and that is Timo.
Best,
Fred Diether
FrediFizzx
> On 15 Aug, 18:25, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
>> Szczepan Bialek <sz.bia...@wp.pl> wrote:
>>
>> (snip)
>>
>> >>Think about it. How can B in the center of a loop induce a current
>> >>in
>> > that loop it is not even touching? What is the mechanism? How can
>> > an E
>> > field be induced in a region where there is not even a B field
>> > (outside a long solenoid or toroid)? One mistake leads to others
>> > which are then attempted to be covered up with bluster. It's only
>> > human!
>>
>> Don't forget the Aharanov-Bohm effect.
>
> I've never understood why people make such a big deal of this effect
> on the quantum scale.
Because it made the magnetic vector potential a reality instead of being
a mathematical artifact.
[snip]
> Is it a retardation effect as expressed in Jefimenko's equations
> giving rise to Faraday's induction law?
>
> Is it an example of A being more physical than B?
Not more physical. A can be combined with the scalar potential, V, to
form a 4-vector potential. It's handy especially in relativistic
quantum physics.
> I think only a relativistic analysis would give an unambiguous
> interpretation.
How and why?
Best,
Fred Diether
Benj
> Benj, do yourself a favor and get a copy of Griffiths' "Intro. to
> Electrodynamics" and read the chapter on Magnetostatics.
>
> [snip more rubbish]
Fred,
What is "rubbish" is that you think that "magnetostatics" is going to
explain causality! Magnetostatics is already "wrong"! Why? Because
things have been simplified by removing retardation. So your idea to
eliminate "rubbish" is to go study something wrong? My suggestion to
you is to actually go get copies of Jefimenkos books, study them,
understand what he did and then report back to us with your
interpretation of exactly where he made his mistake in his
derivations. Jefimenko goes to great lengths to show that Maxwell's
equations are for the most part NOT causal relations as usually
written. Your argument seems to be to simply stand there shouting at
Bill that they "are too!". I'm sorry, but "proof by assertion" belongs
in a political discussion not in a scientific one.
Kick Em Off
Benj, shut up and read your Fresman愀 textbook!
Bill Miller
><snip>
> I think Jefimenko would have pointed that out in his book. :-)
Too late to ask him.
>
>>> Sorry, but the Maxwell equations do show the relationship between E and
>>> B fields. And there is no reason why you can't insert Jefimenko's
>>> causal equations for E and B into,
>>>
>>> curl E = -dB/dt
>>> and
>>> curl B = mu0 J + dE/(c^2 dt)
>>
>> You are tacitly accepting the premise that Maxwell's equations are
>> already causal since you "know" that delta B cause delta E.
>
> No, this is where the confusion is coming from. They are only causal in
> certain situations as in the bar magnet's B field going thru the wire
> loop.
And not in a pair of coils closely coupled, ie a transformer? Jefimenko's
induction concept replaces all existing ideas about how transformers work
also. That is why, I suspect, he spent so much of the Causality book looking
at different induction configurations. If you look at his textbook,
Electricity and Magnetism, you'll see that the *same* equations are fiund --
but solved using Faraday.
> Most solutions to Maxwell's equations require initial and/or boundary
> conditions.
>
>> OK
>>
>> Using your own reasoning that, then curl curl B = mu0 J + dE/(c^2 dt)
>> *should* also mean that a changing E also causes a delta B.
>>
>> But, in spite of many attempts to do so, no one has ever succeeded in
>> neasuring the magnetic field *caused* by delta E. Therefore, by your own
>> requirement that an entity must be measurable, it would seem that it is
>> you; not I that is denying Maxwell!
>
> No. I have a reference at home that indicates this has probably been
> measured.
If you are referring to the one with the superconductors, read it very
carefully. What they measured was the magnetic field associated with radial
current flow within the plates.
I will try to refind it and sent it later. But this also
> requires suitable intial and boundary conditions for a solution. It is
> easy to see that since we have a c^2 in the denominator that this dE/(c^2
> dt) effect is going to be very small compared to mu0J.
Absolutely correct. That's why the superconductor was supposed to settle it.
But a magnetic field identifiable as associated uniquely with dE/dt simply
did not exist.
If you have another reference, I'd love to see it.
>
>> So, what is more pursuasive: An outcome that depends on a mechanism (E_k)
>> that hasn't been directly measured (or has been measured but
>> mis-interpreted). OR: an outcome that *should* exist but has not been
>> measured based on a mechanism (E) that can be measured?
>
> As I said in another post, I believe that E_k is more like part of a
> magnetic field than an electric field.
If so, why does it appear in the terms that Jefimenko derived solely from
Maxwell's "E" equations? (This term also appears in Panofsky and all the
rest.)
>So the mis-interpretation could be on Jefimenko's part. He equates it
>to -dA/dt and to me A is the irrotational part of a B field.
This *might* make some sense except for one aspect of E_k that *has* been
verified experimentally. This is Lentz's law. As Jefimenko has pointed out,
before E_k, there was no convincing explanation for Lentz's law.
Please see text associated with equation 2-4.1 on page 29.
>> BTW, and to prove that Benj and I are not joined at the hip, I don't
>> consider you to be an idiot. Instead, it appears to me -- in this narrow
>> range of inquiry -- you are allowing what you *know* to be true to get in
>> the way of the critical thinking that I have seen you exercise many many
>> times.
>
> I think we are having a very good discussion about what Jefimenko says in
> his book. Don't get me wrong. Jefimenko *could* be right; the jury is
> still out on that so far. What he has said in his book is all very
> interesting. I am mainly just playing the devil's advocate here. :-) But
> I definitely think he is wrong about what he said that a changing B field
> *can't* be a cause. It surely can be a cause with the right setup,
> *macroscopically*.
Would that "right setup" also include transformer action?
> We all know microscopically that all of EM comes from charged particles
> and their motion.
Agreed. And even at a Macro level, they nust obey Maxwell. Jefimenko is
simply Maxwell expressed in terms of charged particles and their motion. And
out of those equations comes E_k.
Now when we drop into QED, the situation may change. But I don't think we
need QED to describe the operation of permanent magnets -- or transformers.
Bill Miller
On Aug 17, 12:05 am, "FrediFizzx" <fredifi...@hotmail.com> wrote:
> Benj, do yourself a favor and get a copy of Griffiths' "Intro. to
> Electrodynamics" and read the chapter on Magnetostatics.
>
> [snip more rubbish]
Fred,
What is "rubbish" is that you think that "magnetostatics" is going to
explain causality! Magnetostatics is already "wrong"! Why? Because
things have been simplified by removing retardation. So your idea to
eliminate "rubbish" is to go study something wrong? My suggestion to
you is to actually go get copies of Jefimenkos books, study them,
understand what he did and then report back to us with your
interpretation of exactly where he made his mistake in his
derivations.
Fred, and pretty much everyone that has replied to this thread seems to
concur that Jefimenko (as well as Panofsky and all the res) in fact have
gotten it "right."
The issue now is one of interpretation of the characteristics of E_k and the
possibility that B (all by itself and with no help from E_k) is capable of
inducing a current in something.
On this subject, something just occurred to me. In every analysis of
receiving antennas that I have seen, the received signal is analyzed
*solely* in terms of the E component of the incident EM wave.
Why?
It could be argued that the E component "due to" H is much smaller than that
from E and therefore can be ignored. But in very weak signal reception,
wherein every nanodB is precious, I would like to suggest that the reason
why the E component induced by H is not considered is because it isn't
there!
<snip>
Bill Miller
"Kick Em Off" <kick...@sofort-mail.de> wrote in message
news:b46d8$4c6a727d$54ad758b$17...@news1.surfino.com...
<snip>>
> Benj, shut up and read your Fresman´s textbook!
If you are going to insult someone's intelligence, it might not be a great
idea to demonstrate your own inability to spell.
Szczepan Białek
"Bill Miller" <kt...@yahoo.com> wrote
news:8cvnpp...@mid.individual.net...
>
> >
> On this subject, something just occurred to me. In every analysis of
> receiving antennas that I have seen, the received signal is analyzed
> *solely* in terms of the E component of the incident EM wave.
>
> Why?
>
> It could be argued that the E component "due to" H is much smaller than
> that from E and therefore can be ignored. But in very weak signal
> reception, wherein every nanodB is precious, I would like to suggest that
> the reason why the E component induced by H is not considered is because
> it isn't there!
So you must find the other way. Heaviside did not: " We may have subsidence
of electric displacement without magnetic
force; but I cannot see any way to produce it." From:
http://en.wikisource.org/wiki/Electromagnetic_effects_of_a_moving_charge
Maxwell proposed the magnetic micro whirls made of massive magnetis
substance.
Now we must see massive electrons. The massive magnetis substance "isn't
there!"
S*
.
ji...@specsol.spam.sux.com
Gibberish.
--
Jim Pennino
Remove .spam.sux to reply.
Benj
> Not sure why you think I am some kind of educator; I'm not. Just a
> self-study student. There is only one educator that I can think of
> right now that frequents this group and that is Timo.
I thought you were moderator for some kind of educational physics
forum? If I'm not mistaken in that, then I presume you are using your
prejudicial ideas that you are expressing here to make sure that none
of Jefimenko's ideas ever are allowed to contact any students of
physics. The usual method is to suggest they are "rubbish" and ban any
person who brings them up ( I guess that would include Bill and me). I
don't know what you call that, but it's sure not the scientific
method.
If you are not the person I was thinking of, then I apologize for
calling you an "educator"!
Benj
> Benj, shut up and read your Fresman´s textbook!
So I can try to be as ignorant as you?
WHY?
Hey I studied under the guys who WROTE the "fresman's" textbook!
Here's you reading a "fresman's" textbook.
FrediFizzx
> On Aug 17, 1:03 am, "FrediFizzx" <fredifi...@hotmail.com> wrote:
>
>> Not sure why you think I am some kind of educator; I'm not. Just a
>> self-study student. There is only one educator that I can think of
>> right now that frequents this group and that is Timo.
>
> I thought you were moderator for some kind of educational physics
> forum?
I am a moderator for sci.physics.foundations, a UseNet discussion group
basically started for *independent* researchers and to keep
sci.physics.research "on their toes". :-) Not necessarily an
educational group thou it can be if someone wishes to be educated by
that process. We allow most all posts on physics if they aren't
experimentally refuted or obviously wrong. We mainly just ask for
politeness. We prefer that posts on special relativity be posted to the
relativity group though we do end up with discussion on relativity from
time to time.
> If I'm not mistaken in that, then I presume you are using your
> prejudicial ideas that you are expressing here to make sure that none
> of Jefimenko's ideas ever are allowed to contact any students of
> physics.
Don't be absurd. I know that is hard for you to not be but you should
try anywise.
> The usual method is to suggest they are "rubbish" and ban any
> person who brings them up ( I guess that would include Bill and me). I
> don't know what you call that, but it's sure not the scientific
> method.
Bill is a nice person; he would not be included in your fantasy about
this. Bill knows how to carry on a polite discussion; something you
ought to learn.
Best,
Fred Diether
FrediFizzx
>
> "Benj" <bja...@iwaynet.net> wrote in message
> news:45840144-d980-428c...@x21g2000yqa.googlegroups.com...
> On Aug 17, 12:05 am, "FrediFizzx" <fredifi...@hotmail.com> wrote:
>
>> Benj, do yourself a favor and get a copy of Griffiths' "Intro. to
>> Electrodynamics" and read the chapter on Magnetostatics.
>>
>> [snip more rubbish]
[looks like googlegroups has hosed the proper attribute marks again]
Benj said:
> Fred,
> What is "rubbish" is that you think that "magnetostatics" is going to
> explain causality! Magnetostatics is already "wrong"! Why? Because
> things have been simplified by removing retardation. So your idea to
> eliminate "rubbish" is to go study something wrong? My suggestion to
> you is to actually go get copies of Jefimenkos books, study them,
> understand what he did and then report back to us with your
> interpretation of exactly where he made his mistake in his
> derivations.
I have Jefimenko's "Causality..." book. You need to pay better
attention; what the heck do you think Bill and I have been discussing?
And we are talking about his *interpretations* of the derivations. I
really don't think he would make any mathematical mistakes in his book.
You are usually offering the wrong advice. You probably shouldn't be
trying to *advise* anyone if you can't get it right.
Bill said:
> Fred, and pretty much everyone that has replied to this thread seems
> to concur that Jefimenko (as well as Panofsky and all the res) in fact
> have gotten it "right."
"Right" as far as his causal equations for E and B go. No problem with
that. They are valid solutions to the Maxwell equations.
> The issue now is one of interpretation of the characteristics of E_k
> and the possibility that B (all by itself and with no help from E_k)
> is capable of inducing a current in something.
Look at the magnetostatic equations and electromagnetic induction in
Griffiths' "Intro. to Electrodynamics". All perfectly well explained
without resorting to Jefimenko's E_k. So I am wondering what is the
necessity of E_k? Doesn't seem to be any real need for it even though
it shows up as "part" of his causal equation for the E field.
> On this subject, something just occurred to me. In every analysis of
> receiving antennas that I have seen, the received signal is analyzed
> *solely* in terms of the E component of the incident EM wave.
>
> Why?
>
> It could be argued that the E component "due to" H is much smaller
> than that from E and therefore can be ignored. But in very weak signal
> reception, wherein every nanodB is precious, I would like to suggest
> that the reason why the E component induced by H is not considered is
> because it isn't there!
For ordinary free space EM radiation, if you know the E component, you
know the B (H) component as well. And... I don't really know what you
mean by "E component induced by H". Why would there be any E component
"induced by H" in this case?
Best,
Fred Diether
Benj
> "Benj" <bjac...@iwaynet.net> wrote in message
> > I thought you were moderator for some kind of educational physics
> > forum?
> We allow most all posts on physics if they aren't
> experimentally refuted or obviously wrong. We mainly just ask for
> politeness. We prefer that posts on special relativity be posted to the
> relativity group though we do end up with discussion on relativity from
> time to time.
Ah. Asking for politeness is one thing. And assertions that are
experimentally refuted (like say the existence of displacement
currents) is obviously what science is all about. But you really admit
you go further into "obviously wrong" territory. So what is "obviously
wrong"? Is a statement that a changing magnetic field does NOT cause a
induced E field "obviously wrong"? Is a statement that CO2 simply
cannot have the climate change effect at levels many are ascribing to
it "wrong"? Is anything that cannot be confirmed in a freshman
textbook "wrong"? Are statements that are contrary to assertions
found in freshman textbooks "wrong"? And what do you DO with "wrong"
statements? I presume you censor them! Say it ain't so!
Fact is what you have called my "fantasy" has just been confirmed by
your own words! QED.
> Bill is a nice person; he would not be included in your fantasy about
> this. Bill knows how to carry on a polite discussion; something you
> ought to learn.
Bill gets to behave any way he chooses. That's what a free speech
forum is about. So do I. I certainly know how to carry on a "polite"
conversation. Whether I choose to do so is my choice. As usual, your
"assumptions" about what I do or do not "know" are pure imagination on
your part. You have no idea who I am or what I know.
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8ctml...@mid.individual.net...
>><snip>
>> I think Jefimenko would have pointed that out in his book. :-)
>
> Too late to ask him.
Yes, it is.
>>>> Sorry, but the Maxwell equations do show the relationship between E
>>>> and B fields. And there is no reason why you can't insert
>>>> Jefimenko's causal equations for E and B into,
>>>>
>>>> curl E = -dB/dt
>>>> and
>>>> curl B = mu0 J + dE/(c^2 dt)
>>>
>>> You are tacitly accepting the premise that Maxwell's equations are
>>> already causal since you "know" that delta B cause delta E.
>>
>> No, this is where the confusion is coming from. They are only causal
>> in certain situations as in the bar magnet's B field going thru the
>> wire loop.
>
> And not in a pair of coils closely coupled, ie a transformer?
What is the primary cause with a transformer? It would be current
injected into the primary. Changing current in the case of AC. A
changing B field is not the primary cause in this case.
Macroscopically.
> Jefimenko's induction concept replaces all existing ideas about how
> transformers work also. That is why, I suspect, he spent so much of
> the Causality book looking at different induction configurations. If
> you look at his textbook, Electricity and Magnetism, you'll see that
> the *same* equations are fiund -- but solved using Faraday.
Same with Griffiths' textbook. So what is the problem he is trying to
solve with his E_k? I really don't see any problem that needs to be
solved other than his erroneous assertion that changing E and B fields
can't cause each other. They certainly can in certain situations which
I have perfectly shown with the bar magnet thru the wire loop.
>> Most solutions to Maxwell's equations require initial and/or boundary
>> conditions.
>>
>>> OK
>>>
>>> Using your own reasoning that, then curl curl B = mu0 J + dE/(c^2
>>> dt) *should* also mean that a changing E also causes a delta B.
>>>
>>> But, in spite of many attempts to do so, no one has ever succeeded
>>> in neasuring the magnetic field *caused* by delta E. Therefore, by
>>> your own requirement that an entity must be measurable, it would
>>> seem that it is you; not I that is denying Maxwell!
>>
>> No. I have a reference at home that indicates this has probably been
>> measured.
>
> If you are referring to the one with the superconductors, read it very
> carefully. What they measured was the magnetic field associated with
> radial current flow within the plates.
>
> I will try to refind it and sent it later. But this also
>> requires suitable intial and boundary conditions for a solution. It
>> is easy to see that since we have a c^2 in the denominator that this
>> dE/(c^2 dt) effect is going to be very small compared to mu0J.
>
> Absolutely correct. That's why the superconductor was supposed to
> settle it. But a magnetic field identifiable as associated uniquely
> with dE/dt simply did not exist.
Well, we can always rearrange the equation to,
curl B - dE/(c^2dt) = mu0 J
Now what do we have? :-) Griffiths points out that this is probably a
better (more logical) way to write that equation. As well as,
curl E + dB/dt = 0
> If you have another reference, I'd love to see it.
I am still trying to remember and find where I ran across it fairly
recently.
>>> So, what is more pursuasive: An outcome that depends on a mechanism
>>> (E_k) that hasn't been directly measured (or has been measured but
>>> mis-interpreted). OR: an outcome that *should* exist but has not
>>> been measured based on a mechanism (E) that can be measured?
>>
>> As I said in another post, I believe that E_k is more like part of a
>> magnetic field than an electric field.
>
> If so, why does it appear in the terms that Jefimenko derived solely
> from Maxwell's "E" equations? (This term also appears in Panofsky and
> all the rest.)
Take a look at how I re-arranged the equation above. Why does B and E
*both* appear on the left side? So Jefimenko really has a "B" field
term in his causal expression for E. Why would there be something wrong
with that? There probably isn't any thing wrong with it other than
perhaps he has fooled himself into thinking otherwise. Sorry, but I
don't have a clue as to what you mean by "derived solely from Maxwell's
"E" equations". You mean div E = rho/eps0 and curl E = -dB/dt? :-)
>>So the mis-interpretation could be on Jefimenko's part. He equates it
>>to -dA/dt and to me A is the irrotational part of a B field.
>
> This *might* make some sense except for one aspect of E_k that *has*
> been verified experimentally. This is Lentz's law. As Jefimenko has
> pointed out, before E_k, there was no convincing explanation for
> Lentz's law.
> Please see text associated with equation 2-4.1 on page 29.
Lenz's law is just a way to help keep track of the direction of induced
current flow. I don't see a problem explaining it with the Lorentz
force law and Newton's third law.
>>> BTW, and to prove that Benj and I are not joined at the hip, I don't
>>> consider you to be an idiot. Instead, it appears to me -- in this
>>> narrow range of inquiry -- you are allowing what you *know* to be
>>> true to get in the way of the critical thinking that I have seen you
>>> exercise many many times.
>>
>> I think we are having a very good discussion about what Jefimenko
>> says in his book. Don't get me wrong. Jefimenko *could* be right;
>> the jury is still out on that so far. What he has said in his book
>> is all very interesting. I am mainly just playing the devil's
>> advocate here. :-) But I definitely think he is wrong about what he
>> said that a changing B field *can't* be a cause. It surely can be a
>> cause with the right setup, *macroscopically*.
>
> Would that "right setup" also include transformer action?
As shown above, no. The primary macroscopic cause there is not a
changing B field. It is changing current. The changing B field is
intermediate and caused by the changing current.
>> We all know microscopically that all of EM comes from charged
>> particles and their motion.
>
> Agreed. And even at a Macro level, they nust obey Maxwell. Jefimenko
> is simply Maxwell expressed in terms of charged particles and their
> motion. And out of those equations comes E_k.
More specifically, charge and current *densities*. And you can
say -dA/dt comes out instead of E_k. Which I think is more descriptive
and is part of a changing magnetic field. Something we already know.
> Now when we drop into QED, the situation may change. But I don't think
> we need QED to describe the operation of permanent magnets -- or
> transformers.
Quantum physics does help in the case of permanent magnet explanations
microscopically. Not needed to explain the operation of transformers.
Best,
Fred Diether
FrediFizzx
>> Now when we drop into QED, the situation may change. But I don't
>> think we need QED to describe the operation of permanent magnets --
>> or transformers.
>
> Quantum physics does help in the case of permanent magnet explanations
> microscopically. Not needed to explain the operation of transformers.
Something to add here about transformers. Why does an iron core make a
transformer more efficient if changing B fields are not involved in
induction? Does Jefimenko have an answer to that?
Best,
Fred Diether
Kick Em Off
> "Kick Em Off" <kick...@sofort-mail.de> wrote in message
> news:b46d8$4c6a727d$54ad758b$17...@news1.surfino.com...
> <snip>>
>
> If you are going to insult someone's intelligence, it might not be a great
> idea to demonstrate your own inability to spell.
>
>
Bill
at first YOU have to study the "Introduction to the fundamentals of the
freshmens textbook":
Feel free to ask help for that.
Kick Em Off
Bill Miller
> Bill Miller schrieb:
>> "Kick Em Off" <kick...@sofort-mail.de> wrote in message
>> news:b46d8$4c6a727d$54ad758b$17...@news1.surfino.com...
>> <snip>>
>>
>> If you are going to insult someone's intelligence, it might not be a
>> great idea to demonstrate your own inability to spell.
>
> Bill
>
> at first YOU have to study the "Introduction to the fundamentals of the
> freshmens textbook":
>
> Feel free to ask help for that.
>
Bill
blackhead
> On 16 Aug, 13:08, Benj <bjac...@iwaynet.net> wrote:
>
>
>
>
>
> > On Aug 16, 1:03 am, "FrediFizzx" <fredifi...@hotmail.com> wrote:
>
> > > > Bzzzzt. Wrong Freddi. Jefimenko's E_k field is in fact a REAL honest
> > > > to God E field.
>
> > > LOL! Show me where someone has measured this E_k field.
>
> > > [snip rubbish]
>
> > So you teach that the EMF induced in a wire is produced by... er...
> > magic?
>
> > you are already lost!
> > Hooper and many others showed that the "one E field" is utter nonsense
> > and that there are really three E fields based upon the properties of
> > the fields. And you don't even believe one of them exists?
>
> > Idiot.
>
> Have any independent institutions carried out tests on Hooper's
> claims?- Hide quoted text -
This Hooper guy looks credible at first glance:
http://www.rexresearch.com/hooper/horizon.htm
B.A., M.A., Ph. D. (University of California Berkeley)
Then he uses "antigravity" further down... oh dear...
It turns out that Nasa did some research into one of his patents on
self-cancelling electromagnetic coils reducing the weight of an object
placed underneath:
http://gltrs.grc.nasa.gov/citations/all/tm-106963.html
And found no weight changes detectable by the instruments used.
> - Show quoted text -
blackhead
> "blackhead" <larryhar...@softhome.net> wrote in message
>
> news:5bff455b-5a64-4ff0...@x25g2000yqj.googlegroups.com...
>
>
>
>
>
> > On 15 Aug, 18:25, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> >> Szczepan Bialek <sz.bia...@wp.pl> wrote:
>
> >> (snip)
>
> >> >>Think about it. How can B in the center of a loop induce a current
> >> >>in
> >> > that loop it is not even touching? What is the mechanism? How can
> >> > an E
> >> > field be induced in a region where there is not even a B field
> >> > (outside a long solenoid or toroid)? One mistake leads to others
> >> > which are then attempted to be covered up with bluster. It's only
> >> > human!
>
> >> Don't forget the Aharanov-Bohm effect.
>
> > I've never understood why people make such a big deal of this effect
> > on the quantum scale.
>
> Because it made the magnetic vector potential a reality instead of being
> a mathematical artifact.
My example, which you snipped, shows this is also true on a macro
scale. Hence I don't see the big deal with it being show on a quantum
level.
> [snip]
>
> > Is it a retardation effect as expressed in Jefimenko's equations
> > giving rise to Faraday's induction law?
>
> > Is it an example of A being more physical than B?
>
> Not more physical. A can be combined with the scalar potential, V, to
> form a 4-vector potential. It's handy especially in relativistic
> quantum physics.
> > I think only a relativistic analysis would give an unambiguous
> > interpretation.
>
> How and why?
Little point commenting here since you snipped the bit I was
commenting on.
> Best,
>
> Fred Diether- Hide quoted text -
Benj
> On 16 Aug, 17:02, blackhead <larryhar...@softhome.net> wrote:
> > Have any independent institutions carried out tests on Hooper's
> > claims?- Hide quoted text -
>
> This Hooper guy looks credible at first glance:
>
> http://www.rexresearch.com/hooper/horizon.htm
>
> B.A., M.A., Ph. D. (University of California Berkeley)
>
> Then he uses "antigravity" further down... oh dear...
The late Dr. Hooper is credible. Go read his book(s). He was an
emeritus professor who like Jefimenko felt that Maxwell needed to be
revisted. Basing his investigations on some classic but out of date
physics texts he generated a bunch of experiments which included the
famed question of "does the magnetic field rotate with the magnet". Of
particular interest was his investigations of Electric fields. As you
may know for a great many years the "one E field" idea was taught.
This idea is that all E fields are really just the "same" thing. He
carefully cataloged the characteristics of E fields and noted that
there were in reality 3 E fields. Those would be the Electrostatic E
field from Charges, The E_k of Jefimenko which is the E field induced
from a Changing A field, and finally the qV xB field of a motionally
induced action. Even though these fields are widely different, they
were once taught to be the SAME E field and freely substituted for
each other.
Hooper then investigated the idea that two magnetic fields in opposite
directions that cancel, do not actually create a zone of "zero"
magnetism, but that both fields remain there active. Many effects
(such as gaussmeters) read zero but he invented experiments to show
that the canceling fields were still present. One such was the "Hooper
generator". This was a bundle of wires with currents running equally
up and down. If you examine the qVxB forces you see that the drift
velocity of the electrons should produce an E field outside the
"generator" in the canceled field region. Such a field was allegedly
measured.
At this point Hooper somehow got the crazy idea that this canceled
field was somehow a gravity generator! That conclusion may have been
influenced by a pile of money a local industrialist provided to fund
his 'antigravity" company. So far as I know his devices were never
shown to really produce gravity modifications of any kind. (Did
produce some financial modifications, however). Anyway, there seems
to be little physics that would suggest that somehow gravity is
connected to magnetism. FAR more interesting in the gravity
department are Jefimenkos books extending Heaviside's work including
EM extensions (by analogy) of gravity equations. GE actually holds a
patent on machines based on these ideas!
But Gravity isn't the Hooper contribution. His investigations of E_k
fields are what really counts. And his attempts to dispel years of EM
dogma. That his gravity theories appear to be a mistake, makes no
difference to that.
OK?
Szczepan Bialek
"blackhead" <larry...@softhome.net> wrote
news:05ff30ee-762c-4c33...@l6g2000yqb.googlegroups.com...
>This Hooper guy looks credible at first glance:
http://www.rexresearch.com/hooper/horizon.htm
"A second modern prejudice, an assumed concept, which has gained
considerable popularity, is one which states "the whole concept of a
magnetic field is a fiction." (6 ~ P. Moon & D.E. Spencer: "Electromagnetism
Without Magnetism: An Historical Sketch"; Amer. J. Phys., vol. 22, p. 120,
1954) "
Gravity, electrostatics and magnetism must be the same, It is known from
ages. The only problem is to this unification.
>Then he uses "antigravity" further down... oh dear...
>It turns out that Nasa did some research into one of his patents on
self-cancelling electromagnetic coils reducing the weight of an object
placed underneath:
http://gltrs.grc.nasa.gov/citations/all/tm-106963.html
>And found no weight changes detectable by the instruments used.
The same NASA discovered that the Moon dust levitate.
S*
Benj
> On Aug 18, 7:37 pm, blackhead <larryhar...@softhome.net> wrote:
> > Then he uses "antigravity" further down... oh dear...
> The late Dr. Hooper is credible. Go read his book(s).
<snip my exposition on Prof. Hooper>
> OK?
I see nobody caught my mistake which I mindlessly copied from Hooper's
book!
I thought you guys were supposed to be sharp?
Benj
> The same NASA discovered that the Moon dust levitate.
> S*
Right. The discovery of stirring up of "moondust" in a vacuum is truly
amazing.
Bill Miller
>
>>> No, this is where the confusion is coming from. They are only causal in
>>> certain situations as in the bar magnet's B field going thru the wire
>>> loop.
>>
>> And not in a pair of coils closely coupled, ie a transformer?
>
> What is the primary cause with a transformer? It would be current
> injected into the primary.
Yes
>Changing current in the case of AC.
I tried to build a DC transformer once... it didn't work very well. (Except
when I first applied power.)
>A changing B field is not the primary cause in this case. Macroscopically.
I think we can get a little bit closer than that. Or we can move further
away and say that the water running throught the turbines in Hoover Dam is
the primary cause.
OK... The primary is physically isolated from the secondary. I can see three
ways that energy can get from the primary to the secondary:
1. An E field interacts with electrons in the secondary and causes them to
move.
2. A B field interacts with electrons in the secondary and causes them to
move.
3. Magic
If we disregard Bob Forward's classic comment that "Any technology, if
sufficiently advanced, is indistinguishable from magic," then we are left
with 1 and 2.
The non-Jefimenko world says that 2 is correct, and we are left with trying
to explain why a B field causes an E field, but an E field does not cause a
B field.
>
>> Jefimenko's induction concept replaces all existing ideas about how
>> transformers work also. That is why, I suspect, he spent so much of the
>> Causality book looking at different induction configurations. If you look
>> at his textbook, Electricity and Magnetism, you'll see that the *same*
>> equations are found -- but solved using Faraday.
>
> Same with Griffiths' textbook. So what is the problem he is trying to
> solve with his E_k? I really don't see any problem that needs to be
> solved
Is this an engineering forum or a physics forum? If it's engineering, then
your question is on topic. If it is physics, then we are supposed to be
trying to understand what is going on -- not looking for solutions.
> other than his erroneous assertion that changing E and B fields
> can't cause each other. They certainly can in certain situations which I
> have perfectly shown with the bar magnet thru the wire loop.
Sorry to disagree. Tossing a magnet does not prove anything if we do not
know the nature of *all* of the fields associated with the magnet. One might
as well say that tossing a white magnet through a loop shows that whiteness
causes an E field. (This silly argument is dismissed with a little paint
thinner. Dismissing the E_k is a bit more complex., since the obvious proof
of its existence -- induced current -- has already been attributed to
changing B.)
And please recall -- as I know you do later -- that nobody has ever
successfully measured the H "caused" by delta E.
>
> Well, we can always rearrange the equation to,
>
> curl B - dE/(c^2dt) = mu0 J
>
> Now what do we have? :-) Griffiths points out that this is probably a
> better (more logical) way to write that equation. As well as,
>
> curl E + dB/dt = 0
Moving stuff from one side of the = sign to the other is no more helpful
than re-arranging the deck chairs on the Titanic.
>
>> If you have another reference, I'd love to see it.
>
> I am still trying to remember and find where I ran across it fairly
> recently.
As a fisherman, I am waiting with baited breath.
>>>> So, what is more pursuasive: An outcome that depends on a mechanism
>>>> (E_k) that hasn't been directly measured (or has been measured but
>>>> mis-interpreted). OR: an outcome that *should* exist but has not been
>>>> measured based on a mechanism (E) that can be measured?
>>>
>>> As I said in another post, I believe that E_k is more like part of a
>>> magnetic field than an electric field.
Well, Benj has pointed out that there appear to be three different E fields.
So yes, it could have some H characteristics.
>>
>> If so, why does it appear in the terms that Jefimenko derived solely from
>> Maxwell's "E" equations? (This term also appears in Panofsky and all the
>> rest.)
>
> Take a look at how I re-arranged the equation above. Why does B and E
> *both* appear on the left side? So Jefimenko really has a "B" field term
> in his causal expression for E.
This seems to be more a matter of re-arranging than useful analysis. Where a
term appears in an equation has no bearing on anything. To the contrary, if
a retardation term does not appear somewhere in *any* equation, I maintain
that the relationships spelled out in the equattion *cannot* be causal
because an equation -- to my way of thinking -- is simply a "snapshot" of
what is happening at the same time.
> Why would there be something wrong with that? There probably isn't any
> thing wrong with it other than perhaps he has fooled himself into thinking
> otherwise. Sorry, but I don't have a clue as to what you mean by "derived
> solely from Maxwell's "E" equations". You mean div E = rho/eps0 and curl
> E = -dB/dt? :-)
What I was trying to say in shorthand was that Jefimenko starts with
expressions that do not explicitly contain E *and* H. See Appendix 2 of
"Causality". IOW "Jefimenko's E" never contained any H.
>
>>>So the mis-interpretation could be on Jefimenko's part. He equates it
>>>to -dA/dt and to me A is the irrotational part of a B field.
>>
>> This *might* make some sense except for one aspect of E_k that *has* been
>> verified experimentally. This is Lentz's law. As Jefimenko has pointed
>> out, before E_k, there was no convincing explanation for Lentz's law.
>> Please see text associated with equation 2-4.1 on page 29.
>
> Lenz's law is just a way to help keep track of the direction of induced
> current flow. I don't see a problem explaining it with the Lorentz force
> law and Newton's third law.
>
I'd *love* to see that! So far I have not seen any explanation of Lentz's
law that did not contain at least one major hand wave.
Bill Miller
> Something to add here about transformers. Why does an iron core make a
> transformer more efficient if changing B fields are not involved in
> induction? Does Jefimenko have an answer to that?
Yep...
Please see example 3-4.2. This is a calculation of induced voltage in free
space. The result (using *only* the terms associated with E_k) contains
mu_0. This result will be modified by the non-free-space mu of the material.
Since that is larger than mu_0, the extra "oomph" is explained.
BTW, all the results in this chapter are exactly equal to those obtained by
conventional Farady-based calculations.
But this introduces a problem. In order to simplify the examples, Jefimenko
deliberately ignored retardation in all his examples. Thus, all his examples
represent *approximate solutions.*
So... if Jefimenko's known approximation is exactly equal to a calculation
based on Faraday, then Faraday *must* be in error by an amount equal to that
introduced by ignoring retardation!
The importance of this may or may not be significant in real-life. But it
should be important if we are examining this from a physics perspective, and
not an engineering one!
blackhead
> "FrediFizzx" <fredifi...@hotmail.com> wrote in message
I'm under the impression that Faraday's law is exact when the present
B is used as in Maxwell's equations.
Jefimenko's equations express Faraday's law in terms of retarded dJ/dt
which is also exact, correct?
Bill Miller
"blackhead" <larry...@softhome.net> wrote in message
news:f2e6078b-bfd7-4ab9...@g17g2000yqe.googlegroups.com...
>I'm under the impression that Faraday's law is exact >when the present
>B is used as in Maxwell's equations.
>Jefimenko's equations express Faraday's law in terms of >retarded dJ/dt
>which is also exact, correct?
Let me re-state.
When Jefimenko's equations are applied without retardation (for simplicity)
the results are identical to those obtained from Faraday.
It seems that it is universally assumed that Faraday's law is exact.
But Jefimenko's equations, when corrected for retardation will -- of
necessity -- provide solutions that are (slightly - to - very much)
different from (and presumably more accurate than) Faraday.
IOW, Faraday, it seems, is less exact than Jefimenko.
Bill Miller
>> On this subject, something just occurred to me. In every analysis of
>> receiving antennas that I have seen, the received signal is analyzed
>> *solely* in terms of the E component of the incident EM wave.
>>
>> Why?
>>
>> It could be argued that the E component "due to" H is much smaller than
>> that from E and therefore can be ignored. But in very weak signal
>> reception, wherein every nanodB is precious, I would like to suggest that
>> the reason why the E component induced by H is not considered is because
>> it isn't there!
>
> For ordinary free space EM radiation, if you know the E component, you
> know the B (H) component as well.
>And... I don't really know what you mean by "E component induced by H".
>Why would there be any E component "induced by H" in this case?
Well, let me try again. Elsewhere you claim that an H field, when "tossed"
through a loop (ie H changing WRT the loop) *causes* a voltage in the loop.
Let me suggest that such a loop is not different in kind from a radio
antenna.
A radio signal (EM) contains separate but related E and H components. Both
the E and H components are changing WRT the antenna. The E field causes a
voltage in the antenna. Yet oddly enough, it appears that the "radio" H
field does not cause any voltage in the antenna.
Why not?
glen herrmannsfeldt
(snip)
> Let me re-state.
> When Jefimenko's equations are applied without retardation
> (for simplicity) the results are identical to those obtained
> from Faraday.
> It seems that it is universally assumed that Faraday's law is exact.
> But Jefimenko's equations, when corrected for retardation will -- of
> necessity -- provide solutions that are (slightly - to - very much)
> different from (and presumably more accurate than) Faraday.
I haven't been following this so closely, and haven't followed
the books recently, either.
This does remind me, though, of the description in the Feynman
Lectures on Physics, and I believe also well described in other
UG level books.
That is, that the far field from a charge moving at constant
velocity points toward or away from the current, not the
previous, position of the charge. That isn't especially obvious
if you consider retardation, but the second term of the field from
a moving charge fixes that up.
Or maybe I completely missed the point.
-- glen
Bill Miller
"glen herrmannsfeldt" <g...@ugcs.caltech.edu> wrote in message
news:i4mv5t$sc3$1...@speranza.aioe.org...
Thanks Glen for "checking in"
I think this amplifies the point that much of what we "learned" in school
"ain't" necessarily so!
All The best,
Bill Miller
FrediFizzx
> "FrediFizzx" <fredifi...@hotmail.com> wrote in message
What is driving the antenna in your case here?
Best,
Fred Diether
PS. On the road right now and didn't bring Jefimenko's book so will
reply to your other messages later.
Bill Miller
> A radio signal (EM) contains separate but related E and H components. Both
> the E and H components are changing WRT the antenna. The E field causes a
> voltage in the antenna. Yet oddly enough, it appears that the "radio" H
> field does not cause any voltage in the antenna.
What is driving the antenna in your case here?
This is a receiving antenna. It is driven by a radio wave. It is terminated
by a resistor with R = the antenna impedance.
Travel safely!
Bill Miller
Benj
> "FrediFizzx" <fredifi...@hotmail.com> wrote in message
>
> news:c8674ec4-a512-43ae...@a36g2000yqc.googlegroups.com...
>
> > A radio signal (EM) contains separate but related E and H components. Both
> > the E and H components are changing WRT the antenna. The E field causes a
> > voltage in the antenna. Yet oddly enough, it appears that the "radio" H
> > field does not cause any voltage in the antenna.
>
> What is driving the antenna in your case here?
>
> This is a receiving antenna. It is driven by a radio wave. It is terminated
> by a resistor with R = the antenna impedance.
>
> Travel safely!
>
> Bill Miller
Bill, an interesting aspect of your example is that there is an EM
theorem that says if one has an EM wave (E and H) incident upon an
aperture, one can replace the waves on that aperture with "equivalent"
currents! Note that since E and H are "locked" they can't be adjusted
separately and the both end up "equivalent" to currents which is
exactly what Jefimenko says is the causal source. And thence those
currents become the new source for the far field of the so-called
"diffracted" wave from that aperture. Interesting stuff!
Bill Miller
Hmmm... I knew of the theorem. It is sometimes used in some aspects of
antenna design, But I never considered it in the Jefimenko context.
Thanks!
Bill Miller
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:c8674ec4-a512-43ae...@a36g2000yqc.googlegroups.com...
>> A radio signal (EM) contains separate but related E and H components.
>> Both
>> the E and H components are changing WRT the antenna. The E field
>> causes a
>> voltage in the antenna. Yet oddly enough, it appears that the "radio"
>> H
>> field does not cause any voltage in the antenna.
>
> What is driving the antenna in your case here?
>
> This is a receiving antenna. It is driven by a radio wave. It is
> terminated by a resistor with R = the antenna impedance.
Surely you have heard of Magnetic Loop antennae?
"A further advantage of magnetic loops used for receiving is that they
respond to the magnetic-field component of the arriving signal; locally
generated rf noise (within 1/6 wavelength) has a generally weak magnetic
component so the noise tends to be rejected. This effect is more marked
at lower frequencies."
http://en.wikipedia.org/wiki/Magnetic_loop
So it is all dependent on the antenna design on whether the E or B
fields are the predominate signal used in the EM radiation being
received.
Best,
Fred Diether
FrediFizzx
>
> "blackhead" <larry...@softhome.net> wrote in message
> news:f2e6078b-bfd7-4ab9...@g17g2000yqe.googlegroups.com...
>
>>I'm under the impression that Faraday's law is exact >when the present
>>B is used as in Maxwell's equations.
>
>>Jefimenko's equations express Faraday's law in terms of >retarded
>>dJ/dt
>>which is also exact, correct?
>
> Let me re-state.
>
> When Jefimenko's equations are applied without retardation (for
> simplicity) the results are identical to those obtained from Faraday.
??? Please explain how you can use Jefimenko's causal equations for E
and B without retardation.
> It seems that it is universally assumed that Faraday's law is exact.
No one yet has shown that curl E + dB/dt = 0 is not "exact" within
experimental error.
> But Jefimenko's equations, when corrected for retardation will -- of
> necessity -- provide solutions that are (slightly - to - very much)
> different from (and presumably more accurate than) Faraday.
>
> IOW, Faraday, it seems, is less exact than Jefimenko.
Again, ??? That seems to be impossible to me since Jefimenko's causal
equations are an exact solution to Maxwell's equations which Faraday's
law is part of the set of equations. I don't think you would ever see
Jefimenko making a statement like that. :-)
Best,
Fred Diether
Bill Miller
<snip>>>
>> IOW, Faraday, it seems, is less exact than Jefimenko.
>
> Again, ??? That seems to be impossible to me since Jefimenko's causal
> equations are an exact solution to Maxwell's equations which Faraday's law
> is part of the set of equations. I don't think you would ever see
> Jefimenko making a statement like that. :-)
>
WRT to your :-) above, actually Jefimenko -- in his oh so very understated
way -- did just that. I'm at home so I don't have my "Causality" handy, but
if you look at your copy (Benj thinks you don't have one.) in the section
discussing this part of *our* discussion, J makes it clear that he feels
his derivation is more accurate,
WRT experimental error, I suspect that you are correct, since retardation is
only empirically important when gamma is significant (it usually isn't) or
distances/time lag are significant (they usually aren't.)
But I'd like to think that reality is always important.
Again, this is s'posed to be a physics discussion forum wherein we are
trying to figure out the underlying reality; not trying to get something to
work "good enough." *That* is engineering. (Please note I am not denigrating
engineering. I "are" one.)
Bill Miller
>>> A radio signal (EM) contains separate but related E and H components.
>>> Both
>>> the E and H components are changing WRT the antenna. The E field causes
>>> a
>>> voltage in the antenna. Yet oddly enough, it appears that the "radio" H
>>> field does not cause any voltage in the antenna.
>>
>> What is driving the antenna in your case here?
>>
>> This is a receiving antenna. It is driven by a radio wave. It is
>> terminated by a resistor with R = the antenna impedance.
>
> Surely you have heard of Magnetic Loop antennae?
>
> "A further advantage of magnetic loops used for receiving is that they
> respond to the magnetic-field component of the arriving signal; locally
> generated rf noise (within 1/6 wavelength) has a generally weak magnetic
> component so the noise tends to be rejected. This effect is more marked at
> lower frequencies."
>
> http://en.wikipedia.org/wiki/Magnetic_loop
>
> So it is all dependent on the antenna design on whether the E or B fields
> are the predominate signal used in the EM radiation being received.
>
> Best,
>
> Fred Diether
I've built more than a few magnetic loop antennas. The Wiki snippet is based
on the assumption (wrong) that a B field does *cause* an E response.
A more rational explanation of the *apparent* noise reduction of a small
tuned loop (STL) is that they are almost always *much* less efficient than
full sized antennas. They are usually deployed at HF where the noise "floor"
is significantly higher than at, say, UHF or above. Consequently, the
perception is that they have a better signal-to-noise ratio whereas they
are -- in fact --
quieter because they are less efficient.
Benj
> Again, ??? That seems to be impossible to me since Jefimenko's causal
> equations are an exact solution to Maxwell's equations which Faraday's
> law is part of the set of equations. I don't think you would ever see
> Jefimenko making a statement like that. :-)
Except that Faraday's law doesn't always work! This is an old
discussion we've had here before, but Feynman notes this in his
lectures. Even the Faraday generator doesn't obey Faraday's law! But
a causal relation obviously must always be correct! Feynman strongly
hints at this though he doesn't spell it out. So you keep harping on
the Curl of E. What exactly is the physical property known as the curl
of E? So far as I know this is a mathematical construct and is not
related to reality by any model I know except maybe Maxwell's ball
bearings but that was pretty bogus! When dealing with reality
generally the method is to horse the equations around (as an old
professor used to say) and measure or calculate the integral of the B
field over an area to get the induced emf around the perimeter of that
area. And that is EXACTLY the very operation that doesn't always
work!
You really own a copy of Jefimenko? I'm amazed...
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8dlutk...@mid.individual.net...
> <snip>>>
>>> IOW, Faraday, it seems, is less exact than Jefimenko.
>>
>> Again, ??? That seems to be impossible to me since Jefimenko's
>> causal equations are an exact solution to Maxwell's equations which
>> Faraday's law is part of the set of equations. I don't think you
>> would ever see Jefimenko making a statement like that. :-)
>>
> Welcome back. Hope the trip was good
Excellent; thank you.
> WRT to your :-) above, actually Jefimenko -- in his oh so very
> understated way -- did just that. I'm at home so I don't have my
> "Causality" handy, but if you look at your copy (Benj thinks you don't
> have one.) in the section discussing this part of *our* discussion, J
> makes it clear that he feels his derivation is more accurate,
Sigh... You are missing the whole point here. Plug J's equation for B
into B of dB/dt then plug his E equation into E of curl E. Does the
left side of the equation equal the right side when you have it arranged
as curl E = -dB/dt? It had better or Jefimenko did something wrong.
See the point now? Saying J's derivation is more accurate makes
absolutely no sense.
I'm sorry, but you and Benj just don't seem to understand what Maxwell's
equations are all about. I strongly urge you both to get a copy of
Griffiths' "Intro. to Electrodynamics". It will hopefully become very
clear after you read that book. He does an excellent job of presenting
it. And... I do believe he was somewhat of a fan of Jefimenko. You
will like what he says on page 444 about Jefimenko's causal equations.
Now, if you look at the potential representation of E and B,
E = - grad V - dA/dt
B = curl A
You will notice J's E_k in the representation for E. A is the
*magnetic* vector potential. So the real question here is why does the
representation for E have a magnetic component in it whilst B does not
have a scalar potential, V, in its representation? J's causal equation
for E *does* have this same magnetic component in it. He just
mislabeled it E_k instead of B_k. The dead give away is that his
expression for it has mu0/4pi in it which is the SI *magnetic*
proportionality constant. This answers your response to the iron core
of a transformer business. Mu is the *magnetic* permeability of matter.
Best,
Fred Diether
FrediFizzx
>
> "FrediFizzx" <fredi...@hotmail.com> wrote in message
> news:8dlu40...@mid.individual.net...
>>>> A radio signal (EM) contains separate but related E and H
>>>> components. Both
>>>> the E and H components are changing WRT the antenna. The E field
>>>> causes a
>>>> voltage in the antenna. Yet oddly enough, it appears that the
>>>> "radio" H
>>>> field does not cause any voltage in the antenna.
>>>
>>> What is driving the antenna in your case here?
>>>
>>> This is a receiving antenna. It is driven by a radio wave. It is
>>> terminated by a resistor with R = the antenna impedance.
>>
>> Surely you have heard of Magnetic Loop antennae?
>>
>> "A further advantage of magnetic loops used for receiving is that
>> they respond to the magnetic-field component of the arriving signal;
>> locally generated rf noise (within 1/6 wavelength) has a generally
>> weak magnetic component so the noise tends to be rejected. This
>> effect is more marked at lower frequencies."
>>
>> http://en.wikipedia.org/wiki/Magnetic_loop
>>
>> So it is all dependent on the antenna design on whether the E or B
>> fields are the predominate signal used in the EM radiation being
>> received.
> I've built more than a few magnetic loop antennas. The Wiki snippet is
> based on the assumption (wrong) that a B field does *cause* an E
> response.
So you are saying that the magnetic loop antenna doesn't respond to the
B field in EM radiation? So explain to us exactly how they work then
please.
> A more rational explanation of the *apparent* noise reduction of a
> small tuned loop (STL) is that they are almost always *much* less
> efficient than full sized antennas. They are usually deployed at HF
> where the noise "floor" is significantly higher than at, say, UHF or
> above. Consequently, the perception is that they have a better
> signal-to-noise ratio whereas they are -- in fact --
> quieter because they are less efficient.
I didn't really care about the noise factor involved with them. Just
exactly how they work in regards to the main EM radiation signal.
Best,
Fred Diether