Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1876304 times)

Offline Rodal

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WallofWolfStreet,

Here is my hand stretched to you for a friendly handshake  :)



(Notice that I put on my WallStreet suit)  ;)
« Last Edit: 06/05/2015 12:13 AM by Rodal »

Offline SeeShells

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I'm going to be open to suggestions in what might be seen in differences between a solid copper sheet constructed frustum and a perforated copper sheet and how the perforated will effect the patterns of reflected microwaves? I decided to make both.

Offline wallofwolfstreet

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And I'll meet you on that one ;D.

This thread is still the number one source of accessible, critical information on the EMdrive in existence.  I'll be doing my best from here on out (no promises!) not to clog it up with side-shows related to minor math issues so we can all enjoy it to the fullest extent. 

Offline rfmwguy

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I'm going to be open to suggestions in what might be seen in differences between a solid copper sheet constructed frustum and a perforated copper sheet and how the perforated will effect the patterns of reflected microwaves? I decided to make both.

I'm definitely going w/mesh. Skin depth is sub-micron level @ 2.4 GHz, so that shouldn't be an issue. Holes in mesh will be transparent @ 2.4 GHz. Will be an interesting comparison to solid Cu.

Offline TheTraveller

Driven mainly by the $4k cost of a 100W 3.85GHz Rf amp, versus $2k for a 100W 2.45GHz Rf amp and the help Roger Shawyer has provided in getting my EMDrive Calculator operational, I have decided to adopt the EW/Mulletron/Iulian copper frustum design but with a slightly altered length to get TE013 resonance at 2.45GHz.

Will shortly provide data on the TE012 & TE013 resonance frequencies of the EW frustum (calculated as per Shawyer) plus what needs to be changed to achieve resonance at Shawyer's suggested TE013.

As EWs has a variable narrow band Rf generator, would be interesting to see what they get exciting their frustum in TE013 mode at the frequency Shawyer claims will generate resonance. They may need to modify their antenna design and feedin point on the side wall.
« Last Edit: 06/05/2015 12:35 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline rfmwguy

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Driven mainly by the $4k cost of a 100W 3.85GHz Rf amp, versus $2k for a 100W 2.45GHz Rf amp and the help Roger Shawyer has provided in getting my EMDrive Calculator operational, I have decided to adopt the EW/Mulletron/Iulian copper frustum design but with a slightly altered length to get TE013 resonance at 2.45GHz.

Will shortly provide data on the TE012 & TE013 resonance frequencies of the EW frustum (calculated as per Shawyer) plus what needs to be changed to achieve resonance at Shawyer's suggested TE013.

As EWs has a variable narrow band Rf generator, would be interesting to see what they get exciting their frustum in TE013 mode at the frequency Shawyer claims will generate resonance. They may need to modify their antenna design and feedin point on the side wall.

Broken record: Careful of the 4KV bias voltage  :P

Offline SeeShells

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holes vs not

Offline deltaMass

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Is this a Bombshell?
Or is this a Meh!?

At least have a look...
http://phys.org/news/2015-06-physicists-pressure.html

Offline TheTraveller

holes vs not

Nice info. Is a keeper.

My issue would be getting a smooth & accurate roll of the frustum side walls if using other than a solid sheet. Not saying it can't be done but maybe not KISS.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

Driven mainly by the $4k cost of a 100W 3.85GHz Rf amp, versus $2k for a 100W 2.45GHz Rf amp and the help Roger Shawyer has provided in getting my EMDrive Calculator operational, I have decided to adopt the EW/Mulletron/Iulian copper frustum design but with a slightly altered length to get TE013 resonance at 2.45GHz.

Will shortly provide data on the TE012 & TE013 resonance frequencies of the EW frustum (calculated as per Shawyer) plus what needs to be changed to achieve resonance at Shawyer's suggested TE013.

As EWs has a variable narrow band Rf generator, would be interesting to see what they get exciting their frustum in TE013 mode at the frequency Shawyer claims will generate resonance. They may need to modify their antenna design and feedin point on the side wall.

Broken record: Careful of the 4KV bias voltage  :P

Not using a magnetron. Instead using a variable frequently narrow band Rf gen with a 100W Rf amp. Similar setup to EW.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline deltaMass

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Is this a Bombshell?
Or is this a Meh!?

At least have a look...
http://phys.org/news/2015-06-physicists-pressure.html
IMHO my take:

<<"There is no conceptual problem with the momentum of light if the light is reflected, for example from a mirror or the dust particles of a comet, because here the momentum balance is very simple: twice the incident momentum causes motion, the incident and the reflected one," Leonhardt said. "If, however, part of the light is transmitted, then the transmitted light in the material needs to be taken into account. There it matters whether the Abraham or Minkowski momentum is carried by the transmitted light, as it affects the net balance of momentum, whether it is positive or negative. In Abraham's case the net balance leads to a push, in Minkowski's to a pull."
Yes, the EmDrive connection is, I agree, tenuous. However, what if a mechanism existed such that the narrow end experienced a push, and the wide end a pull? One has to throw the kitchen sink at this perhaps - evanescent waves, attenuation, partial transmission, you name it...

Perhaps this effect (narrow push, wide pull, or vice versa) can be deliberately engineered. Is CoM violated? I suspect strongly that it is not. But the asymmetry is appealing.

Online aero

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Been making a little progress in my understanding of Scheme and Meep programming. Attached find a big end view of a modified Brady cone. The big end is modeled as concentric metal rings, one 64th of an inch wide, separated by one 64th of an inch of vacuum. To get an idea of scale, recall that the big end diameter is about 11 inches.

The cavity resonates with very nearly the same frequency and Q value as does the cavity with a solid end.
Retired, working interesting problems

Offline Rodal

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PHOTON ACCELERATION

A related microwave experiment by Joshi et al, in 1992 [95] was able to show
that the frequency of microwave radiation contained in a cavity can be up-shifted
to give a broadband spectrum, in the presence of an ionization front produced by
an ultraviolet laser pulse. These results provided the first clear indication that the
photon acceleration mechanism was possibly taking place


http://bit.ly/1FY2inV




This Russian website has this book on

Theory of Photon Acceleration
J T Mendonca



http://bit.ly/1M9gPyy

by one of the original discoverers of what is known as photon acceleration.

This website version of the book is only shown here for research purposes, for researchers such as @Notsosureofit, conducting such research.

People are warned that this book is copyrighted and published by The Institute of Physics, and if interested, you are advised to purchase the book from an authorized bookseller, for example here is Amazon

http://amzn.to/1FxkrXd

instead of relying on the copy from the Russian website.


<<The concept of photon acceleration appeared quite recently in plasma physics. It
is a simple and general concept associated with electromagnetic wave propagation,
and can be used to describe a large number of effects occurring not only in
plasmas but also in other optical media. Photon acceleration is so simple that it
could be considered a trivial concept, if it were not a subtle one.
Let us first try to define the concept. The best way to do it is to establish a
comparison between this and a few other well-known concepts, such as with refraction.
For instance, photon acceleration can be seen as a space–time refraction.
Everybody knows that refraction is the change of direction suffered by a light
beam when it crosses the boundary between two optical media. In more technical
terms we can say that the wavevector associated with this light beam changes,
because the properties of the optical medium vary in space.
We can imagine a symmetric situation where the properties of the optical
medium are constant in space but vary in time. Now the light wavevector remains
constant (the usual refraction does not occur here) but the light frequency changes.
This effect, which is as universal as the usual refraction, can be called time
refraction. A more general situation can also occur, where the optical medium
changes in both space and time and the resulting space–time refraction effect
coincides with what is now commonly called photon acceleration.
Another natural comparison can be established with the nonlinear wave processes,
because photon acceleration is likewise responsible for the transfer of
energy from one region of the electromagnetic wave spectrum to another. The
main differences are that photon acceleration is a non-resonant wave process,
because it can allow for the transfer of electromagnetic energy from one region of
the spectrum to an arbitrarily different one, with no selection rules>>
« Last Edit: 06/05/2015 03:42 AM by Rodal »

Online WarpTech

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This is for those of you who believe the refractive index of the vacuum is simply a "scalar field". It is not, it is a tensor field and behaves like an anisotropic crystal.

https://www.researchgate.net/publication/1968721_Effective_refractive_index_tensor_for_weak_field_gravity

Effective refractive index tensor for weak-field gravity
Petarpa Boonserm †, Celine Cattoen ‡, Tristan Faber §, Matt Visser ∥, and Silke Weinfurtner ¶
School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington,
P.O.Box 600, Wellington, New Zealand

Abstract.

Gravitational lensing in a weak but otherwise arbitrary gravitational field can be described in terms of a 3 × 3 tensor, the “effective refractive index”. If the sources generating the gravitational field all have small internal fluxes, stresses, and pressures, then this tensor is automatically isotropic and the “effective refractive index” is simply a scalar that can be determined in terms of a classic result involving the Newtonian gravitational potential. In contrast if anisotropic stresses are ever important then the gravitational field acts similarly to an anisotropic crystal. We derive simple formulae for the refractive index tensor, and indicate some situations in which this will be important.

gr-qc/0411034; 8 November 2004;
Revised 10 March 2005; LATEX-ed 7 February 2008

Enjoy!

Offline SeeShells

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I'm sure most have seen this but it's great to visualize a pulse of photons traveling down a coke bottle. What I found interesting is when the pulse reaches the top of the bottle and the area that shrinks in dimension. The wave front traveling in the center remains at the same speed  but look at the sidewall of the bottle shaped like the frustum the wave is still the same but the distance traveled on the surface of the sidewall is longer. Just found this an interesting visual.

Offline Rodal

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....
I'm sure most have seen this but it's great to visualize a pulse of photons traveling down a coke bottle. What I found interesting is when the pulse reaches the top of the bottle and the area that shrinks in dimension. The wave front traveling in the center remains at the same speed  but look at the sidewall of the bottle shaped like the frustum the wave is still the same but the distance traveled on the surface of the sidewall is longer. Just found this an interesting visual.
I had never seen this before.  Thanks a million for posting it !!!

What caught my attention also was what I have been thinking about during the past few days: the incredible fact that photons are not constant inside the cavity but that a huge amount can be produced  or destroyed.  I find it fascinating to see the gradient of photon density within the cavity.
« Last Edit: 06/05/2015 03:45 AM by Rodal »

Offline Rodal

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On the reluctance of physicists to talk about photon acceleration and instead use other terminology

Theory of Photon Acceleration
J T Mendonca

<<This section contains a few concluding remarks. We have started with very simple
ideas concerning the processes of time refraction and time reflection, which correspond
to a natural extension of the familiar concepts of refraction and reflection
into the space–time domain.
The frequency shift resulting from these basic processes is what we call
photon acceleration. We have shown that it can occur in a large variety of physical
situations, in plasmas, in optical fibres or other optical media, and that it is more
effective when the space–time disturbance of the medium travels with a velocity
nearly equal to that of the photons.
Presently, a significant fraction of the physics community is still reluctant to
talk about photon acceleration and prefers to use other terms such as frequency
shift or phase modulation. This is not, in principle, a big problem, because what
is important in physics is to have an accurate view of the physical processes,
independent of the way they are known. However, the choice of the words is
never completely innocent or arbitrary, and reflects the ideas that we have about
the physical reality.
We have shown in this work that the photons in a medium are subjected to
a force, proportional to the time derivative of the refractive index. Furthermore,
their dynamical interaction with electrostatic waves in a plasma is very similar to
that of a charged particle (an electron or an ion) interacting with the same wave.
In particular, photons can oscillate and can be trapped in the wavefield. On
the other hand, the plasma waves can be damped by photon Landau damping, in
the same way as they are Landau damped by the electrons.

We have also found that an effective photon mass, and an equivalent electric
charge (or a dipole) for the photons in a medium, could be defined. This shows
that our familiar view of photons as particles with no rest mass, and with no
electric charge, can only apply to ‘bare’ photons moving in a vacuum and not to
‘dressed’ photons moving in a background medium. This means that we should
not deny for photons what we accept as true for other particles: that, by receiving
energy from the fields with which they interact, they are energized or, in other
words, they are accelerated.
We can still argue that photons correspond to a particle description of the
electromagnetic field, and that more generally, a wave description is necessary.
But the same is also true for the other fields and for the other particles.
This means that the use of photon acceleration as a genuine physical concept
can lead to a more global view of the physical processes and of the elementary
interactions between the various particles and the various fields. What, at first
sight, is seen as a more fashionable choice of terminology can lead us to ask new
questions and eventually to get a deeper understanding about physics.
As an example, we could say that the equivalent charge of a photon in a
plasma is nothing but a different way of describing the well-known ponderomotive
force, or radiation pressure effects
. However, the fact that we were able to
isolate the new concept of an equivalent charge led us immediately to the problem
of secondary radiation emitted by accelerated photons, such as the photon
ondulator effects of the photon transition radiation. Other questions related to this
concept, but not considered here, are the possibility of photon bending in a static
magnetic field or the attraction between two parallel photon beams.
We can also explore the idea of photon acceleration as a particular example
of particle acceleration by a time-varying mean field. Such a mean field process
could operate not only with photons and the electromagnetic field, but also with
other particles and with other fields. We saw in this chapter that the ideas of
photon acceleration in an optical medium can be extrapolated to the case of
photons interacting in a vacuum with a gravitational field, or to neutrinos moving
in a dense plasma.
These different mean field processes involve the electromagnetic, the weak
and the gravitational interactions. Similar processes can also be found for the
strong interaction. In particular, the possibility of particle acceleration by the
non-stationary nuclear matter produced by relativistic heavy ion collisions [20] is
presently being explored >>

« Last Edit: 06/05/2015 03:43 AM by Rodal »

Offline SeeShells

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....
I'm sure most have seen this but it's great to visualize a pulse of photons traveling down a coke bottle. What I found interesting is when the pulse reaches the top of the bottle and the area that shrinks in dimension. The wave front traveling in the center remains at the same speed  but look at the sidewall of the bottle shaped like the frustum the wave is still the same but the distance traveled on the surface of the sidewall is longer. Just found this an interesting visual.
I had never seen this before, particularly enjoyable coming from my alma mater.  Thanks a million for posting it !!!

What caught my attention also was what I have been thinking about during the past few days: the incredible fact that photons are not constant inside the cavity but that a huge amount can be produced  or destroyed.  I find it fascinating to see the gradient of photon density within the cavity.
Gladly it looks very much like I visualized but much better. We used some of the very same technology to image accelerating proton packets in the Super Conductor Collider. We used a Streak Camera from Hamamatsu Photonics to image the packet and detect any abnormalities in that packet, go/no go situation.

It would be interesting to see a packet traveling down a beaker shaped like a Frustum with reflecting mirrors to just see the waveform interactions.

Offline deltaMass

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While watching the light in the "plastic frustum" (nice find Shells!) I was thinking about what handles one has on the phase of the light as it bounces around inside. Although unthinkable a decade or so ago, now we can actually do mechanical movement up into the GHz domain using monolayer graphene sheets. These of course can be coated with a single atomic layer of anything you fancy.  They can also be switched between transmitting and reflecting. So we can play all sorts of games with such a sheet inserted at right angles to the frustum axis. Just a crazy thought.

Offline SeeShells

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....
I'm sure most have seen this but it's great to visualize a pulse of photons traveling down a coke bottle. What I found interesting is when the pulse reaches the top of the bottle and the area that shrinks in dimension. The wave front traveling in the center remains at the same speed  but look at the sidewall of the bottle shaped like the frustum the wave is still the same but the distance traveled on the surface of the sidewall is longer. Just found this an interesting visual.
I had never seen this before, particularly enjoyable coming from my alma mater.  Thanks a million for posting it !!!

What caught my attention also was what I have been thinking about during the past few days: the incredible fact that photons are not constant inside the cavity but that a huge amount can be produced  or destroyed.  I find it fascinating to see the gradient of photon density within the cavity.
Gladly it looks very much like I visualized but much better. We used some of the very same technology to image accelerating proton packets in the Super Conductor Collider. We used a Streak Camera from Hamamatsu Photonics to image the packet and detect any abnormalities in that packet, go/no go situation.

It would be interesting to see a packet traveling down a beaker shaped like a Frustum with reflecting mirrors to just see the waveform interactions.
I saw this, oh, I don't know last year I guess. If you have any pull or contacts at MIT it would be a visual delight to see a pulse travel down a plastic/glass frustum with mirrors at each end.
This is frustrating and pushing our math to see what's happening in the frustum, maybe a visual would get two or more brain cells firing off...at the same time.

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