Hi,I've been interested in reactionless propulsion for a long time now, and one concept that seems to crop up a lot is rotating magnetic fields.Whether it's Searl, Podkletnov, the Marcus device , it seems to be a recurring concept that (perhaps) a rotating magnetic field (particularly one that is rotating very fast or uses superconductors) *may* be able to affect the space-time fabric and hence create a reactionless force. I'm a rational guy and I don't have much time for the pseudoscience, but I think we have to keep an open mind.So I was wondering what you folks thought about this as a propulsion concept, are you aware of any recent experiments, have you done any experiments yourself, does this have potential.Very interested to hear any replies, Thank you.
I did an experiment myself where we rotated a magnetic field symmetrically about it's axis. By vxB=E there should be a change in charge.
I came to the conclusion later that changing magnetic fields radiate. That is information travels about the magnetic field at the speed of light away from the source.
magnetic field lines that were over a certain distance and angularly rotating could eventually exceed the speed of light.
Thanks for the replies,I apologise in advance if this is silly science, but I came across a Dr. John Brandenburg, who claims that gravity is linked to electromagnetism via radiation pressure and the Poynting vector.
Quote from: dustinthewind on 08/06/2019 01:21 pmI did an experiment myself where we rotated a magnetic field symmetrically about it's axis. By vxB=E there should be a change in charge.That equation is wrong (cross product of velocity and magnetic field is proportional to force due to magnetic field, it doesn't generate and E field.) Even if you had the correct equation, your statement is based on a complete misunderstanding. Rotating a magnet around its axis of symmetry does not generally result in a changing magnetic field, so the effect you were looking for was never actually expected to exist to begin with.
Quote from: dustinthewind on 08/06/2019 01:21 pmI came to the conclusion later that changing magnetic fields radiate. That is information travels about the magnetic field at the speed of light away from the source. This is a conclusion you could find in any electrodynamics textbook. Accelerating charges radiate. Changing magnetic fields generally imply accelerating charges (caveats exist related to things like constant velocity magnets) Information about accelerating charges propagates at the speed of light along with the electromagnetic radiation. Quote from: dustinthewind on 08/06/2019 01:21 pmmagnetic field lines that were over a certain distance and angularly rotating could eventually exceed the speed of light. Clearly incorrect conclusion since as stated just previously, everything involved propagates at the speed of light. It seems like here you are considering something similar to how a shadow can move at a high apparent speed, because it does not represent anything physically moving. The information conveyed by the shadow actually propagates at the speed of light from the source, and there is nothing strange about it arriving at 2 different, distant and widely separated points at a similar time.A lot of the rest of your post that I didn't respond to basically seems to be you putting different concepts together in a very non-rigorous fashion that doesn't make any sense if you were to try to explain it rigorously. It demonstrates a lack of understanding of the concepts you are talking about, or even what the terms you are using mean.This manner of throwing things together is similar to some of the things referenced by SigmaDelta. It sure sounds fancy to throw around words like "rotating magnets" while talking about space-time, but it doesn't necessarily mean anything. Most scientist simply ignore such concepts, because they aren't even remotely plausible to the point where it seems like there isn't even a coherent way to state them.
sigh, it is not wrong.
The force F acting on a particle of electric charge q with instantaneous velocity v, due to an external electric field E and magnetic field B,
The B field is not a shadow to some one that thinks of the field as a structure.
Quote from: SigmaDelta on 08/07/2019 12:00 amThanks for the replies,I apologise in advance if this is silly science, but I came across a Dr. John Brandenburg, who claims that gravity is linked to electromagnetism via radiation pressure and the Poynting vector. He immediately discredits himself by claiming that radiation pressure is different than electric and magnetic forces. If you take the electric and magnetic fields of an electromagnetic wave, and calculate the force they exert on a charge (or a metal plate, etc.) you exactly get radiation pressure. It makes no sense whatsoever to count it as a separate force, you would be double counting.
Quote from: meberbs on 08/07/2019 12:50 amQuote from: SigmaDelta on 08/07/2019 12:00 amThanks for the replies,I apologise in advance if this is silly science, but I came across a Dr. John Brandenburg, who claims that gravity is linked to electromagnetism via radiation pressure and the Poynting vector. He immediately discredits himself by claiming that radiation pressure is different than electric and magnetic forces. If you take the electric and magnetic fields of an electromagnetic wave, and calculate the force they exert on a charge (or a metal plate, etc.) you exactly get radiation pressure. It makes no sense whatsoever to count it as a separate force, you would be double counting.Just to clarify, are you are saying Lorentz forces are exactly and always the radiation pressure of photons? Or do you mean only when in the form of propagating EM waves? Thanks.
Quote from: Bob012345 on 08/07/2019 05:39 pmQuote from: meberbs on 08/07/2019 12:50 amQuote from: SigmaDelta on 08/07/2019 12:00 amThanks for the replies,I apologise in advance if this is silly science, but I came across a Dr. John Brandenburg, who claims that gravity is linked to electromagnetism via radiation pressure and the Poynting vector. He immediately discredits himself by claiming that radiation pressure is different than electric and magnetic forces. If you take the electric and magnetic fields of an electromagnetic wave, and calculate the force they exert on a charge (or a metal plate, etc.) you exactly get radiation pressure. It makes no sense whatsoever to count it as a separate force, you would be double counting.Just to clarify, are you are saying Lorentz forces are exactly and always the radiation pressure of photons? Or do you mean only when in the form of propagating EM waves? Thanks.The second one, the forces due to propagating EM waves can be determined purely from the fields and the charges they act on. Magnetic fields can exist in steady state with no propagating EM waves, and still result in Lorentz forces. (Virtual photons and related quantum mechanical descriptions of such things are beyond the scope of what is relevant for what I was saying.)
Thanks. But would you expect the same instantaneous Lorentz force on a charge or current carrying wire whether the source of the B field is a wave or a steady state situation if at that moment the B field is the same?
Quote from: dustinthewind on 08/07/2019 01:03 amsigh, it is not wrong. Yes, it is; the most basic reason being you've neglected the force term in your previous equation. If you're going to rearrange the equation, you've got two options:qE = F - q(VxB) orq(VxB) = F - qEEither option may have situational use, but neither has intrinsic value. Read a bit further down in your wiki link:QuoteThe force F acting on a particle of electric charge q with instantaneous velocity v, due to an external electric field E and magnetic field B,Bold mine. 'External' means E and B fields exist (or don't exist) completely independently of anything else that's happening. Either field can take on any value, including zero, without any impact on the other. Changing the steady-state magnitude of either field can influence the force experienced by a charged particle, but will never change the value of the other field. Nor can it somehow alter the amount of charge in your test fixture, and vice versa.qE = q(VxB) = F has no meaning.
In fact it was shown that so long as a current loop is used to measure induced EMFs from the motion of the disk and magnet it is not possible to tell if the magnetic field does or does not rotate with the magnet.
I can't really tell what you've done with your test setup, but it sounds like you might have (sort of) replicated step 2 of the Faraday Paradox. See below:https://en.wikipedia.org/wiki/Faraday_paradox#The_procedureOf course, as usually the case with well-developed theories, there doesn't actually exist any paradox; only misapplication of the theory itself.
Several experiments have been proposed using electrostatic measurements or electron beams to resolve the issue, but apparently none have been successfully performed to date.[citation needed]
Quote from: dustinthewind on 08/07/2019 01:03 amThe B field is not a shadow to some one that thinks of the field as a structure. The point of the shadow analogy isn't to illustrate the the field has no structure, but to illustrate the fact that the apparent motion of the field has no meaning, because no part of the field is actually traveling in that superluminal direction. This is a simple variation of the Lighthouse paradox.Think of it this way instead. Go outside, and look up at the stars. Now, start spinning in circles. You should now "see" a bunch of stars circling you at very superluminal velocities. Of course, they're not actually doing anything of the sort. You're simply moving your field of view across the sky. In addition to your field of view, you could cast a beam light (or shadow) of your own on any number of stars as rapidly as you wish. Eventually. It'll still take many, many years for that beam to arrive, no matter how fast you sweep your hand across the sky.
If you hold the view that the field flux is a physical entity, it does rotate ...
We were discussing only the B field - hence vxB=E not E+vxB=E. The E field from the B field is a separate entity as that of a charge's, what I call its "non-relativistic electric field". I don't disagree there.
Quote from: dustinthewind on 08/08/2019 06:51 amWe were discussing only the B field - hence vxB=E not E+vxB=E. The E field from the B field is a separate entity as that of a charge's, what I call its "non-relativistic electric field". I don't disagree there.Can you see the difference between the letter "E", and the letter "F"? Let me repeat that in lower case (although lower case variables normally would mean something different.) The difference between the letter "e" and the letter "f"The equation you just wrote is nonsensical. You have the same variable E on both sides, so just subtract it off and you are left with v x B = 0. This is only true in the special cases that v = 0, B = 0, or v and B are parallel. The correct equation, (using lower case for e and f, since you failed to read it correctly in the previous post, or in the links provided, is f = q*e +q* (vxB) The magnetic field directly generates a force, it doesn't generate some pseudo E-field to do its work for it. That wouldn't even make sense.When you are saying you "don't disagree," you are actually saying that you understood nothing of 1's post, because 1 stated that the E field and B field are completely separate and unrelated in this (quasi-static) case. You are saying that the B -field generates an E-Field, and you are claiming so in a fundamentally inconsistent way. (In non-quasi-static cases, it is changing B fields that generate an E-Field, but before I try to explain what these words mean, you need to recognize the algebraic mistakes you are making.)With that said, it doesn't sound like you understood a single word of 1's post. Hopefully now that I cleared up what seems to be some confusion with variables on your part, you will understand it better, so go back and re-read 1's post again, At least until you comprehend the fact that your equations are completely wrong, and any prediction that spinning a magnet on its axis of symmetry should do anything is a complete misapplication of the theory, and that is over a century old news.
I think the problem is rather your desire to see a lack of understanding. It was already made clear in the rest of the text it was understood E_q+vxB=E_full such that E_q is not the same as E_full. Maybe it was lazy to lack the annotation at that point but the rest of the text makes it clear.Yes an electron moving relative to a magnetic source does observe an E field in it's moving frame and the reason for the force. The magnetic field being a velocity dependent dipole electric field.
We were discussing only the B field - hence vxB=E not E+vxB=E.
...what I call...
In fact when the capacitor is spun in the magnetic field it does observe an effective change in charge from the source of the magnetic field, let that sink in - yet when the magnet is spun no change in charge.
This E field is entirely from the B field, not a static charge, but appears as a change in charge as observed from a large rotating structure, such as the concentric ring capacitor. This is because different parts of the capacitor have different velocity vectors, so each charge in the capacitor observes a different dipole electric field from the solenoid, which is a magnetic effect.
If the B field radiates to deposit over space, becuse new information about the B field doesn't travel faster than light then changes in the B field propagate at the speed of light.
Light and Shadow are bedfellows.
Quote from: dustinthewind on 08/08/2019 08:44 pmI think the problem is rather your desire to see a lack of understanding. It was already made clear in the rest of the text it was understood E_q+vxB=E_full such that E_q is not the same as E_full. Maybe it was lazy to lack the annotation at that point but the rest of the text makes it clear.Yes an electron moving relative to a magnetic source does observe an E field in it's moving frame and the reason for the force. The magnetic field being a velocity dependent dipole electric field. No, your equation is simply 100% wrong with or without the annotation. There is only one E field. There is no additional E field that is proportional to the velocity of the charge that is moving in a magnetic field. You now are starting to talk about different reference frames, and conflating the results from different reference frames, which is a great way to get incorrect answers. Electromagnetic fields in special relativity transform between reference frames as a tensor, where the tensor is a function of both the electric and magnetic fields in each frame. Before trying to discuss different reference frames, first you need to understand how electrodynamics works in a single frame.Also, please don't make false ad hominem attacks like claiming that I desire to see a lack of understanding. What I actually desire is for you to understand.
Quote from: dustinthewind on 08/08/2019 06:51 amWe were discussing only the B field - hence vxB=E not E+vxB=E.If we're only discussing the B field, then your equation shouldn't have E anywhere in it. And you're still neglecting the force term. This is the third time this has been pointed out to you. If you're not going to address that, then this entire discussion should be terminated.
Quote from: dustinthewind on 08/08/2019 06:51 am...what I call... Stop doing this. If you want to have any meaningful discussion, you need to apply proper terminology in your posts. "Tilting" and "pancaking" fields have no meaning to anyone else. "Non-relativistic electric field" is also poorly defined, as all fields can be made relativistic by simply changing reference frames. It sounds like you're trying to declare a rest-frame field of something, but it's very unclear of what.
Quote from: dustinthewind on 08/08/2019 06:51 am In fact when the capacitor is spun in the magnetic field it does observe an effective change in charge from the source of the magnetic field, let that sink in - yet when the magnet is spun no change in charge.Let what sink in? The wiki page perfectly resolves the difference between the two scenarios. There's nothing unexpected here. I suspect this might be one of your fundamental roadblocks. Capacitors don't "change" charge; they displace charge. Electrons are moved such that one plate has more negative charge than positive, and the other has more positive charge than negative. The magnitude of this displacement is what's given/used in capacitor formulae. The net charge over the entire device can almost always be considered to be zero.
Quote from: dustinthewind on 08/08/2019 06:51 amThis E field is entirely from the B field, not a static charge, but appears as a change in charge as observed from a large rotating structure, such as the concentric ring capacitor. This is because different parts of the capacitor have different velocity vectors, so each charge in the capacitor observes a different dipole electric field from the solenoid, which is a magnetic effect.No. If you're switching reference frames, an external B field in one reference frame manifests as external E and B fields in another. This is precisely the kind of field you were trying to ignore in the beginning of your post. This is why I stressed that the E and B fields can take on arbitrary values.
In a more rigorous E&M treatment of your setup, where the exact cause of the creation your B field would be considered, then you might be able calculate some sort of charge-based effect at a distance. But if you're going to start your calculations at a place where the B field is simply already there and you don't really care why (which is fine for many applications), then the creation of an E field due to switching reference frames needs to be treated the same way. It's simply, "just there". There is no change in charge, and certainly not a local one.
Quote from: dustinthewind on 08/08/2019 06:51 amIf the B field radiates to deposit over space, becuse new information about the B field doesn't travel faster than light then changes in the B field propagate at the speed of light.B fields by themselves don't have radiating or propagating solutions, but otherwise this is fine. Quote from: dustinthewind on 08/08/2019 06:51 amLight and Shadow are bedfellows.Of course they are. Just as is the idea that rotating field lines can exceed the speed of light. It has no physical meaning.
Quote from: 1 on 08/08/2019 10:00 pmQuote from: dustinthewind on 08/08/2019 06:51 amWe were discussing only the B field - hence vxB=E not E+vxB=E.If we're only discussing the B field, then your equation shouldn't have E anywhere in it. And you're still neglecting the force term. This is the third time this has been pointed out to you. If you're not going to address that, then this entire discussion should be terminated.Having only a B field means you can neglect E in E+vxB=E_full. Force is just taking the equation times q the charge. Go ahead put a q in there if it suits you.
The experiment starts with a B field in the lab frame and only a B field in the lab frame. If you assume it rotates axially you have to transform it into an E field in the lab frame which is that transformation. It's already known E and B fields can transform. This is located a few paragraphs above discussing how you get pancaked electric fields.