Author Topic: EM Drive Developments - related to space flight applications - Thread 9  (Read 1798792 times)

Offline X_RaY

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

« Last Edit: 05/15/2017 05:11 pm by X_RaY »

Offline TheTraveller

Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
It Is Time For The EmDrive To Come Out Of The Shadows

Offline Stormbringer

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I can't decide if this is more topically related to this thread or to the Mach effect thread...

https://phys.org/news/2017-05-nature-great-puzzles-expansion-universe.html

Essentially it is about quantum vacuum energy dark energy and counter balancing small scale forces that lead to a tiny inflationary effect in cosmology. The relevance here is no one working on EM drives know what would cause the effect observed if it is not an artifact of experimental error. It could be this or it could be that or the other. So here is an "other" for us to consider. :)
When antigravity is outlawed only outlaws will have antigravity.

Offline X_RaY

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?
« Last Edit: 05/15/2017 07:19 pm by X_RaY »

Offline ThatOtherGuy

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GROAN

Offline flux_capacitor

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?

It's like TT is talking only about bouncing photons as corpuscular particles only, and you're talking about the effects of electromagnetic waves. Both aspects need to be taken into account, as light can be described as a group of discrete quanta but also as waves. Otherwise you two… are not on the same wavelength ;)

Offline X_RaY

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?

It's like TT is talking only about bouncing photons as corpuscular particles only, and you're talking about the effects of electromagnetic waves. Both aspects need to be taken into account, as light can be described as a group of discrete quanta but also as waves. Otherwise you two… are not on the same wavelength ;)
I think you are talking about probability of detection of a quanta(photon) at a specific location at a defined point in time. I don't think the particle picture is much helpful** in the case of a cavity resonator with dimensions comparebile to the wavelength because of, a wavenumber k applies to the ortogonal directions also(in fact the wavenumber is a complex value). The wave funktion seems blurred (but is well defined {sine /cosine}) and satisfy N*pi in all directions because of the boundary conditions.

** I did not say it isnt applicable at all!  ::)

Add
you can be sure I take the partial view into account
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1611123#msg1611123
:) different context but... very enlightening
« Last Edit: 05/15/2017 08:56 pm by X_RaY »

Offline rq3

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?

Answer 1) Sure it can. That's why the coherence length of a laser depends on its end optics.
Answer 2) See answer 1 above.

Question 1) How's that rotary test rig on a bookshelf coming along. Got any new and nifty computer generated images without any data you can share? I mean, it's only been a couple of years now. Whoops, I mean, going on THREE years. Please help. I've been holding my breath, and I'm turning blue. NOT.

I'll wait for SeaShells and Monomorphic before I exhale, but thanks for the entertainment you provide.



Offline masterharper1082

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?
I'll bite... change the boundary condition through use of a different material or coating on the sidewall?

mh

Offline meberbs

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The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.
For a simple closed cavity in resonance, everything is the same phase essentially by definition. With all of the overlapping waves, there is no real good way to define the phase of the overlapping, and counter-propagating waves. Whether the endplates are spherical or flat may have some effect on Q (I think someone did some sims to compare, but I forget the results), but the reason would have to do with how much dissipation ends up in the endplates as a result.

Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?

Answer 1) Sure it can. That's why the coherence length of a laser depends on its end optics.
Answer 2) See answer 1 above.
Comparisons to lasers can lead to incorrect conclusions, because for lasers the dimensions typically are not on the order of the wavelength.

I believe the best way to translate "number of bounces" into something with physical meaning is probably mode shape, since mode shape is based on the result of the various paths the overlapping waves need to follow to meet the boundary conditions. Mode shape will obviously affect Q, but since changing mode shape requires significant changes to the size of the cavity or the frequency, it is then a trick question depending on what is held constant. Mode shape will be somewhat affected by things like changing endplate shape, but spherical endplates don't seem to change the characteristics of the pattern significantly, so "number of bounces" would be basically the same.

...

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?
I'll bite... change the boundary condition through use of a different material or coating on the sidewall?

mh
As long as different material is a metal, the only effective thing that changes is resistance, which affects Q as you would expect. (Does not change radiation pressure on the sides though, other than it scaling with Q.)

If you put a dielectric coating the inner surface with metal on the outside, there will still be the metal boundary condition, and I don't expect this to lead to any kind of desired result. If you don't have the metal on the outside, the RF will just radiate through the dielectric completely destroying the resonance, and it would be potentially dangerous depending on the power level. There is a such thing as dielectric waveguides, but applying that to a resonating cavity that at least vaguely resembles the emDrive would be difficult at best.

Edit: minor typos
« Last Edit: 05/16/2017 05:48 pm by meberbs »

Offline OnlyMe

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Can cavity design alter the number of direct end to end photon reflections vs side wall reflecting photons?

What happens to cavity Q and trapped photon life inside the cavity if the number of side wall reflecting photons can be reduced?
Seems you don't realize that the photon wavelength in this kind of cavity resonators is of the order of the structure.


BTW
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095

Sure do.

TE013 = 3 x 1/2 effective guide waves between end plates.

So you are saying that using convex small end and concave big end spherical end plates will have NO EFFECT on the ratio of side wall reflecting to end plate reflecting photons? If so are you also saying that building other than flat end plate cavities is a waste of effort?
The concave and convex endplate guarantee that the wave is reflected at the same phase over the full area of the endplates. Therefore the counterpropagating waves form a more narrow bandwidth standing wave pattern than in the case of the flat plates. Flat end plates leads to phase distorsion and  inperfect constructive interferences what lowers the Q.

So please explain, what exactly do you think you can do to protect the wave from interacting with the sidewall as it must satisfy the boundary conditions of the conductive wall material?

It's like TT is talking only about bouncing photons as corpuscular particles only, and you're talking about the effects of electromagnetic waves. Both aspects need to be taken into account, as light can be described as a group of discrete quanta but also as waves. Otherwise you two… are not on the same wavelength ;)

The difficulty is that microwaves in a cavity don't really act like photons bouncing around, and aren't "light". They are better described and understood as waves than as photons. TT continues to confuse things by mixing terms and returning to the bouncing photon description.

And yes even long wavelength EM radiation interacts with atoms in quantifiable ways. But the longer the wavelength the more difficult it is to describe EM radiation as discrete photons.

As seen in some of the responses and general discussion, it would be far better to drop the photon analogy and deal with how microwaves as waves propagate and interact within and with the cavity walls.

Offline Space Ghost 1962

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Suggest that a better mathematical model for waves in the cavity may be a caustic (see Caustic_(optics) and Caustic_(mathematics)).

The simplest example of a caustic is the shadows you see of ripples in a pool. They are formed from the lensing action of variable density/path of light through the medium. In terms of mathematics, its the folding of the manifold created by a density wave, such as one created by a trapped microwave E/M field of finite size.

Caustics are sometimes used in high powered beam forming situations, like with certain kinds of particle accelerators. They have also been used to describe natural energy beaming in cosmic and planetary phenomena.

You can have group force terms of statistical phase reinforcement with caustics, where the manifold solutions permit.

Perhaps this might fit this application better than wavelength resonant cavity models including lasers do?

Sorry for butting in.

Offline graybeardsyseng

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Suggest that a better mathematical model for waves in the cavity may be a caustic (see Caustic_(optics) and Caustic_(mathematics)).

The simplest example of a caustic is the shadows you see of ripples in a pool. They are formed from the lensing action of variable density/path of light through the medium. In terms of mathematics, its the folding of the manifold created by a density wave, such as one created by a trapped microwave E/M field of finite size.

Caustics are sometimes used in high powered beam forming situations, like with certain kinds of particle accelerators. They have also been used to describe natural energy beaming in cosmic and planetary phenomena.

You can have group force terms of statistical phase reinforcement with caustics, where the manifold solutions permit.

Perhaps this might fit this application better than wavelength resonant cavity models including lasers do?

Sorry for butting in.

SpaceGhost -

Excellent comment - hadn't thought of caustics in some time but I do think you are on to something.   In a past project  some years ago we used caustics in both power RF for beam forming (millimeter radar applications) as well as very low power interception and DF (direction finding) applications - particularly as related to  interferometry solutions.   For those interested in particular I would suggest reading on volume or volumetric caustics as applied to RF cavities.  Don't have a reference link as I am on a VERY slow wifi;  will try to find some and post later. 

Hmmm - I think I will do some re-reading of past posts with caustics in mind.

Herman
graybeardsyseng
EMdrive - finally - microwaves are good for something other than heating ramen noodles and leftover pizza ;-)

Offline SeeShells

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This was one of the first primers I read almost two years ago when I started my quest for  actions within the closed cavity of an EMDrive. https://www.microwaves101.com/encyclopedias/waveguide-primer
Then referenced many times...
https://archive.org/stream/ClassicalElectrodynamics/Jackson-ClassicalElectrodynamics#page/n253/mode/2up

There still exists some confusion (and rightly so) of the actions of microwaves in a closed resonating asymmetric waveguide. When your trying to comprehend actions of Electric, Magnetic fields, photons, trapped and accelerating particles, possibly plasma generation,  different TE TM modes, even evanescent wave actions and then how this Betty Crocker Blender maelstrom interacts with the materials of the frustum... IMHO it becomes much much more than just simple bouncing photons.

Needless to say I'm still learning and finding new material to explain the why. Currently I've over 2500 papers and links to something relevant with this drive.

My Very Best,
Shell

Corrected writing mistakes.
« Last Edit: 05/16/2017 04:26 pm by SeeShells »

Offline Space Ghost 1962

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Hi Shell,

Yes, its been interesting reading the experiences, seeing the battle over maintaining consistent physics, explorations into mathematical physics territory, rationalizations for experiential beliefs, etc.

What's limited my understanding of this phenomena has been the lack of a "macro level" concept to explain the transient force, that can be extended down to the microwave fundamentals "nano level", then up through the engineering "recipe" or "brew" to where power scaling shows where we've put the physics together wrong.

Your own experiences with melted metal have reminded me of when beam forming went wrong, and deposited a large amount of electrons on the wavefront of the beam to a portion of the beam pipe.

So it's all along seemed like somehow an enormous amount, fair fraction of a mol of electrons is suddenly lurching on device power on. (In test beams, we could measure the momentum of the beam in transients too.)

But in the progression of what I've read from this thread (and elsewhere), have never found convincing means to connect the dots. As I've shared privately before, there's examples in the past of hundred newton force levels.

Photons don't have the momentum (even at the NIF the momentum is too small), so electron/proton carriers of force could only do this. But to get this size of effect, you'd need a huge group effect, and it would have to be virtual particles in an ensemble (for various stability reasons). Like a child's "teeter-totter", it would have to slam down to a side. An asymmetric group momentum vector transform. That's the macro level I haven't seen in all that's been posted here.

(FWIW, my daughter is getting her PhD in physics at the moment, and she's using the same copy of J.D. Jackson that me and her mom used for graduate physics. High current E/M microwave has some surprises when you apply it to accelerators (me - surprisingly relates to propulsion too), fusion plasmas (her mom), and planetary/cosmic phenomena (her), where RTI for the interface/"impedance match" is different (Euler function solution)). )

Perhaps the problem is in the means to express the problem, in that neither statistical physics description (in gross) nor quantum mechanical (partitioning), nor plasma (domains/levels) seem to work as the mathematical physics framework. If we use abstract mathematics we could create an abstraction that works this backwards, much in the same way my daughter's professor restated Maxwell's equations into a supersymmetic form (NB something one should not do in practice for other reasons but he did it because he could).

In this case, you'd assume the existence of the ensemble necessary to explain the transient (group mass, density, velocity), working in the frame of reference (hard part - what are the bounds?), with the group's action defined as a manifold expressed/folded by the mode of the cavity, as in the form of a Hamiltonian of this caustic. That's vaguely what I've been looking for. But I can't make this work when I develop it further. It needs a asymmetry to work, but the only asymmetry present is the mode/cavity, and how in the world does that fight the stochastic processes that brings it back to ordinary stat mech, which gives radiant heating solutions you'd expect.

(I could give you this in 20 pages of a partially completed theory paper, but fewer of you would get the drift, and when you invoke topology to deal with the manifold, it's very tedious work. As it is, my posts are often TL;DR enough as it is - am long winded. But I really have appreciated the rigor of some of the posts here, partially because I haven't had to type them and check them ;) )


Offline rfmwguy

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That is not entirely true Dave. http://emdrive.wiki/Experimental_Results

Shell



A surprise disclosure of performance, while exciting, is not productive without public evidence. This applies to EmDrive, megadrive or whateverdrive somebody wants to promote and get funding for. Other than monomorphic, I've seen no one other than myself provide a video diary/pics/data of the trials and tribulations of designing, building and testing one of these things. That includes Woodward and his many allies.

Secret labs and promises will kill this and other similar projects IMHO.

If people want to play hide and seek with their efforts, I simply look at it as a funding scheme. Data, pics and vids get my attention, not clever words, arrogant authoritarianism or a spew of equations to try and impress the readership.

I'll check back from time to time for real results. I suggest spreadsheets, pics and vids to get my attention. If you don't want my attention, keep on keyboarding. - Back to the shadows - Dave
A third party plugging in information on wiki is of little interest, sorry.

Offline rfmwguy

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Dr Woodward fairly regularly provides updates of his experimental work via his mailing list, thus it's hardly hidden away - as Paul rightly notes.

Adam

A surprise disclosure of performance, while exciting, is not productive without public evidence. This applies to EmDrive, megadrive or whateverdrive somebody wants to promote and get funding for. Other than monomorphic, I've seen no one other than myself provide a video diary/pics/data of the trials and tribulations of designing, building and testing one of these things. That includes Woodward and his many allies.

Secret labs and promises will kill this and other similar projects IMHO.

If people want to play hide and seek with their efforts, I simply look at it as a funding scheme. Data, pics and vids get my attention, not clever words, arrogant authoritarianism or a spew of equations to try and impress the readership.

I'll check back from time to time for real results. I suggest spreadsheets, pics and vids to get my attention. If you don't want my attention, keep on keyboarding. - Back to the shadows - Dave

Dave:

"That includes Woodward and his many allies."

Dr. Woodward has been publishing his Mach-Effect conjectures and test results in peer reviewed publications since 1988 and has had a number of pictures and videos of his test setup and results published on the web as well.  He just doesn't choose to frequent NSF.com...

Best, Paul M.
These were not what I would call public disclosure...a private email list. I've read some that I was copied on but never got the message that these were meant to be made public.

Offline SeeShells

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That is not entirely true Dave. http://emdrive.wiki/Experimental_Results

Shell



A surprise disclosure of performance, while exciting, is not productive without public evidence. This applies to EmDrive, megadrive or whateverdrive somebody wants to promote and get funding for. Other than monomorphic, I've seen no one other than myself provide a video diary/pics/data of the trials and tribulations of designing, building and testing one of these things. That includes Woodward and his many allies.

Secret labs and promises will kill this and other similar projects IMHO.

If people want to play hide and seek with their efforts, I simply look at it as a funding scheme. Data, pics and vids get my attention, not clever words, arrogant authoritarianism or a spew of equations to try and impress the readership.

I'll check back from time to time for real results. I suggest spreadsheets, pics and vids to get my attention. If you don't want my attention, keep on keyboarding. - Back to the shadows - Dave
A third party plugging in information on wiki is of little interest, sorry.
No problem Dave, it was meant for more than just you and you can take it how you see it.

Shell

Offline Monomorphic

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RF caustics using 2.47Ghz directional antenna and a wavy 40cm wide dialectric block with relative permittivity of 2.15.

Offline Space Ghost 1962

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Now, how would that all occur as a single impulse? If it could, that would be your "lurch".

First, it couldn't because there's no means.

Second, it would violate conservation of momentum. You'd expect stochastic behavior. Which would result in random movement/heat.

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