Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1802815 times)

Online Rodal

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...Considering these simple facts I've decided to make my Frustum(s) so that it will be able to change the internal dimensions to fine tune from my own best estimate and this is why I plan on building 3 different frustums and all will be adjustable. I stated designing the flexibility in my first one when I joined this group. ...
That's a fantastic idea  :)


I'm working on a paper that shows what happens if you extend the cone into much smaller small diameters than what have been tried up to now.  While extending the truncated cone into a cylinder is easy and has been done (using the cylinder to change the variable length) extending the cone, keeping the same cone angle , going to smaller and smaller bases and exploring what happens with Q, and  the thrust, is one thing we need to explore.


Remember the one I'm doing in a Hexagonal shape? I've been designing to taking it to a point and making the small end plate section detachable so I can insert different sizes as I go down to smaller and a longer Frustum. Plus the octagonal shape is stronger and less prone to thermal effects and add the holes allowing heat and pressure to escape I'l remove some of the worries of a totally enclosed Frustum. The biggie and the most interesting to me is I should be able to "see" inside through the holes like a microwave oven's mesh front at higher powers I expect to see plasma discharges.

Good enough? ;)

Shell

I think that's fantastically clever, inventive, imaginative and very original !!!! 

« Last Edit: 06/18/2015 07:37 PM by Rodal »

Offline Flyby

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Could you make the frustum in such a way that it is modular, with ring sections that can be added. It is more work to build, but the modularity would allow easier research.

I recon, it might be easier to first have proof that this thing works, before investing more time and dedication into improving the EMdrive...

Offline flux_capacitor

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For any interested: I found this book on the shelves at work yesterday.  It's an unabridged 1955 reprint of a 1912 work by H.Bateman, exhaustively referenced, but to stuff that's probably unobtanium.  It still refers to the aether and references GR as a 'recent theory' :)
Note the stamp on the front "Litton Library".  This was in the library of Litton's AMECOM division which was purchased by Northrop Grumman in 2001 (I came along with the purchase!).  The last time it was checked out of the library was 1970 :)
If anyone cares I can scan any portions of this which might be of interest.

The book is available as an online viewable PDF (alas not searchable, pages are images). EDIT: whole PDF (1915 version!) attached below.


For those who would be interested to purchase the book, some more recent copies (2010) are available on Amazon.
« Last Edit: 06/18/2015 07:46 PM by flux_capacitor »

Offline SeeShells

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...Considering these simple facts I've decided to make my Frustum(s) so that it will be able to change the internal dimensions to fine tune from my own best estimate and this is why I plan on building 3 different frustums and all will be adjustable. I stated designing the flexibility in my first one when I joined this group. ...
That's a fantastic idea  :)


I'm working on a paper that shows what happens if you extend the cone into much smaller small diameters than what have been tried up to now.  While extending the truncated cone into a cylinder is easy and has been done (using the cylinder to change the variable length) extending the cone, keeping the same cone angle , going to smaller and smaller bases and exploring what happens with Q, and  the thrust, is one thing we need to explore.


Remember the one I'm doing in a Hexagonal shape? I've been designing to taking it to a point and making the small end plate section detachable so I can insert different sizes as I go down to smaller and a longer Frustum. Plus the octagonal shape is stronger and less prone to thermal effects and add the holes allowing heat and pressure to escape I'l remove some of the worries of a totally enclosed Frustum. The biggie and the most interesting to me is I should be able to "see" inside through the holes like a microwave oven's mesh front at higher powers I expect to see plasma discharges.

Good enough? ;)

Shell

I think that's fantastically clever, inventive, imaginative and very original !!!!

Thanks. Let's hope it's all of that. Right now I need to get out to the shop so I can play and have fun. And it is FUN!!!

Offline ElizabethGreene

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I'm working on a paper that shows what happens if you extend the cone into much smaller small diameters than what have been tried up to now.  While extending the truncated cone into a cylinder is easy and has been done (using the cylinder to change the variable length) extending the cone, keeping the same cone angle , going to smaller and smaller bases and exploring what happens with Q, and  the thrust, is one thing we need to explore.

It should not be terribly difficult to make a resonator where you can change the small-end plate diameter.  Make a pointed cone.  Then change the frustrum small end diameter by sticking circular end plates of various sizes into it.  To make it mechanically robust the end plates can be held in place by nylon bolts.

This presupposes that our desired phenomenon wouldn't be suppressed by the overhanging bits of copper extending beyond the end plate.

I have an idea about how to make an adjustable angle cone too, but it needs more thought.
Something like this:

... and the iris from StarGate

(...and now I see someone else posted my idea within the last 4 hours.  <expletive/>)
« Last Edit: 06/18/2015 07:49 PM by ElizabethGreene »

Offline deuteragenie

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I would be back to the need for a more powerful machine as soon as I increased the computational lattice looking for any RF energy outside of the cavity. (like modeling a screen end, instead of a solid plate) By using a totally enclosed cavity with quarter inch perfect metal skin, I'm not concerned with Meep detecting anything external to the cavity.

My solution is still the same Harminv generated answers. Harminv does seem to work a little better in 3D, at least it is easier to find resonance in my current setup. In order to use the frequency solver, I think I would need to recompile and install meep from source. I'm still running the binary downloaded from the Debian web site. This is an older version and I don't think it includes the frequency solver, unless you are referming to MPB, then I know that requires a compile from source in order to install it.

I generate the time solution with every run. It only adds the time needed to output the data files which is not much. My problem is converting the 4D data set then piecing it together. In particular the colors usually come out very weak and faded so there is not a lot to see. That is because the field strength near the antenna is high, while it is low in the areas of interest. This becomes a scaling problem for the color map. If I get a good set of images I will send them off to Tom Ligon who is good enough to convert them to a movie, then I will post the movie. But don't hold your breath.

Aero,

May I make a suggestion that might help out your efforts?
If you made out instructions on how to use MEEP, and supplied the source file which is to be run, would it possible do you think to distribute it and get others to run particular parts of the Time Run - then have the people running it send you the finished parts and you can then stitch together?
[/quote]

Don't bother aero with this: they are good tutorials on how to RUN meep on the Internet.  Unfortunately, the documentation on how to set up a model is badly lacking.

Offline deuteragenie

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I generate the time solution with every run. It only adds the time needed to output the data files which is not much. My problem is converting the 4D data set then piecing it together. In particular the colors usually come out very weak and faded so there is not a lot to see. That is because the field strength near the antenna is high, while it is low in the areas of interest. This becomes a scaling problem for the color map. If I get a good set of images I will send them off to Tom Ligon who is good enough to convert them to a movie, then I will post the movie. But don't hold your breath.

I used this tutorial to make the animation I posted before: http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial
It is straightforward.

For your color map, you should use an exponential or log map, that will intensify the "weak" colors.

Offline WarpTech

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Just came across a very interesting paper;

http://arxiv.org/pdf/0708.3519.pdf

Photons inside a waveguide as massive particles
Zhi-Yong Wang1, Cai-Dong Xiong
"In the paper, we show that there exists a close analogy between the behavior of de
Broglie matter waves and that of electromagnetic waves inside a hollow waveguide, such that the guided photons can be treated as free massive particles subject to a relativistic quantum-mechanical equation. Inspired by the effective rest mass of guided photons and the zitterbewegung phenomenon of the Dirac electron, at variance with the well-known Higgs mechanism we present some different heuristic ideas on the origin of mass."

Offline aero

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I would be back to the need for a more powerful machine as soon as I increased the computational lattice looking for any RF energy outside of the cavity. (like modeling a screen end, instead of a solid plate) By using a totally enclosed cavity with quarter inch perfect metal skin, I'm not concerned with Meep detecting anything external to the cavity.

My solution is still the same Harminv generated answers. Harminv does seem to work a little better in 3D, at least it is easier to find resonance in my current setup. In order to use the frequency solver, I think I would need to recompile and install meep from source. I'm still running the binary downloaded from the Debian web site. This is an older version and I don't think it includes the frequency solver, unless you are referming to MPB, then I know that requires a compile from source in order to install it.

I generate the time solution with every run. It only adds the time needed to output the data files which is not much. My problem is converting the 4D data set then piecing it together. In particular the colors usually come out very weak and faded so there is not a lot to see. That is because the field strength near the antenna is high, while it is low in the areas of interest. This becomes a scaling problem for the color map. If I get a good set of images I will send them off to Tom Ligon who is good enough to convert them to a movie, then I will post the movie. But don't hold your breath.

Aero,

May I make a suggestion that might help out your efforts?
If you made out instructions on how to use MEEP, and supplied the source file which is to be run, would it possible do you think to distribute it and get others to run particular parts of the Time Run - then have the people running it send you the finished parts and you can then stitch together?
[/quote]

That's a nice thought, but it wouldn't help. Meep runs the whole problem end to end, storing the Yee lattice in memory until the end, then writing the data files. Meep can write the data files at intermediate time points but forwarding that data to a different computer wouldn't help the wall clock time problem.

What would help would be for an expert in the use of ParaView (or someone who wants to try it) to volunteer to reduce the 4-D data set to something visual. I could upload the data set to Google drive to be downloaded from there.
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Offline rfmwguy

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...Considering these simple facts I've decided to make my Frustum(s) so that it will be able to change the internal dimensions to fine tune from my own best estimate and this is why I plan on building 3 different frustums and all will be adjustable. I stated designing the flexibility in my first one when I joined this group. ...
That's a fantastic idea  :)


I'm working on a paper that shows what happens if you extend the cone into much smaller small diameters than what have been tried up to now.  While extending the truncated cone into a cylinder is easy and has been done (using the cylinder to change the variable length) extending the cone, keeping the same cone angle , going to smaller and smaller bases and exploring what happens with Q, and  the thrust, is one thing we need to explore.


Remember the one I'm doing in a Hexagonal shape? I've been designing to taking it to a point and making the small end plate section detachable so I can insert different sizes as I go down to smaller and a longer Frustum. Plus the octagonal shape is stronger and less prone to thermal effects and add the holes allowing heat and pressure to escape I'l remove some of the worries of a totally enclosed Frustum. The biggie and the most interesting to me is I should be able to "see" inside through the holes like a microwave oven's mesh front at higher powers I expect to see plasma discharges.

Good enough? ;)

Shell

Hey, no fair Shell, "stealing my mesh idea"  ;)

I agree, it will be interesting. Also, break out the patchouli incense stick...I plan to place a "smoke stick" under the frustum to watch for convective air currents as they pass around and THRU the frustum. Also, I will post a video by this weekend (on my ustream page), demo-ing my balance scale (a simple mechanical balance to augment the more sensitive digital scale). Validation...since digital scales could be influenced by even low RF power.

Offline WarpTech

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Just came across a very interesting paper;

http://arxiv.org/pdf/0708.3519.pdf

Photons inside a waveguide as massive particles
Zhi-Yong Wang1, Cai-Dong Xiong
"In the paper, we show that there exists a close analogy between the behavior of de
Broglie matter waves and that of electromagnetic waves inside a hollow waveguide, such that the guided photons can be treated as free massive particles subject to a relativistic quantum-mechanical equation. Inspired by the effective rest mass of guided photons and the zitterbewegung phenomenon of the Dirac electron, at variance with the well-known Higgs mechanism we present some different heuristic ideas on the origin of mass."

So, apparently photons in a waveguide may be treated identically to De Broglie waves of massive particles. The photons have a rest mass determined by the waveguide cut-off where vg => 0;

mphoton = h/cλc

and have relativistic momentum;

p = mphoton*vg/√(1 - (vg/c)2)

As the waves reach the cut-off end of the waveguide, their momentum goes to zero and the frustum must gain that amount of rest mass. This process should happen with a magnetron, because the output is a Negative E-field, pulsed at 60Hz (or 50Hz) and this negative value exponentially decays to zero. The magnetron's microwaves have a negative DC bias, right out of the gun.

http://www.cpii.com/docs/related/2/Mag%20tech%20art.pdf

I believe that this process stores mass at the front of the frustum that builds over time, walking the CM forward until there is enough pressure to push it. The resonant microwaves, IMO like Greg Egan, have nothing to do with the thrust. The Q when using a magnetron however, may be proportional the stored DC current level as well as the resonance since both will grow together until heat losses overcome the addition of more current. It is essentially, charging up an inductor, L,

dI(t) = (V/L)dt

In this case, f = 60Hz, not GHz.

The force dF = B.H*dS  (S for area), is due to the B-field pressure, which escapes through the copper because it is DC. The AC skin effect does not apply so the field cannot be shielded by copper.
Todd




Online Rodal

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Just came across a very interesting paper;

http://arxiv.org/pdf/0708.3519.pdf

Photons inside a waveguide as massive particles
Zhi-Yong Wang1, Cai-Dong Xiong
"In the paper, we show that there exists a close analogy between the behavior of de
Broglie matter waves and that of electromagnetic waves inside a hollow waveguide, such that the guided photons can be treated as free massive particles subject to a relativistic quantum-mechanical equation. Inspired by the effective rest mass of guided photons and the zitterbewegung phenomenon of the Dirac electron, at variance with the well-known Higgs mechanism we present some different heuristic ideas on the origin of mass."

So, apparently photons in a waveguide may be treated identically to De Broglie waves of massive particles. The photons have a rest mass determined by the waveguide cut-off where vg => 0;

mphoton = h/cλc

and have relativistic momentum;

p = mphoton*vg/√(1 - (vg/c)2)

As the waves reach the cut-off end of the waveguide, their momentum goes to zero and the frustum must gain that amount of rest mass. This process should happen with a magnetron, because the output is a Negative E-field, pulsed at 60Hz (or 50Hz) and this negative value exponentially decays to zero. The magnetron's microwaves have a negative DC bias, right out of the gun.

http://www.cpii.com/docs/related/2/Mag%20tech%20art.pdf

I believe that this process stores mass at the front of the frustum that builds over time, walking the CM forward until there is enough pressure to push it. The resonant microwaves, IMO like Greg Egan, have nothing to do with the thrust. The Q when using a magnetron however, may be proportional the stored DC current level as well as the resonance since both will grow together until heat losses overcome the addition of more current. It is essentially, charging up an inductor, L,

dI(t) = (V/L)dt

In this case, f = 60Hz, not GHz.

The force dF = B.H*dS  (S for area), is due to the B-field pressure, which escapes through the copper because it is DC. The AC skin effect does not apply so the field cannot be shielded by copper.
Todd

1) This theory should be subject to nullification easily then, by measuring the DC component for example, is that right?  Measuring the DC component should be an important part of any researcher's report

2) Next remains to show how can this exceed the force/InputPower of a perfectly collimated photon rocket by several orders of magnitude (from a factor of 84 for the reverse NASA test in vacuum to a factor of 320,000  in Yang's case)

3) Next, can one show that the effective "mass" thereby lost is consonant with the claimed acceleration?

4) Next, what are the consequences of this theory with respect to the "energy paradox" put forth by frobnicat and deltaMass?
« Last Edit: 06/18/2015 10:33 PM by Rodal »

Offline aero

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Quote
Enclose your model with a larger model and thereby limiting the number of calculations and keep the this walls?

Just a thought.

Shell 

No, the problem is resolution. Meep requires a minimum of 8 to 10 lattice (pixels) points per wavelength in order to accurately calculate the fields. That converts to ~ 0.01 meter pixel spacing at 3GHz. 1/32 inch skin thickness is like 0.0008 m so to resolve the skin, meep needs pixel density like 100 times what is needed to calculate the fields. If the model of the skin passes between pixels, meep doesn't see the skin at all. While meep provides averaging techniques which help ameliorate this problem, those techniques can only go so far. And the clincher is that the CPU time goes up as 28 power with doubling the resolution while the memory requirements go up as 216, at least that is the way I recall it. Bottom line is that if meep doesn't abort for lack of memory, then my wife makes me kill it for lack of sleep. (My computer is in her bedroom and I'd like to keep sharing it.)

I think, as far as Meep results go, our weakness is in reducing the data that I can generate, not so much in generating more data. And I have h5topng installed, so I can view the timelapse animations almost at will at least for 2-D runs. If others have h5topng they could easily do so too, by downloading data files that I'm quite willing to upload.

Speaking of that, I now have several conic frustum models put together in one program, (If-then-elseif-elseif ...) and can easily add more so if you could agree on what frustum model you would like to see the raw data for, I only need to add 4 data points within an "elseif" to incorporate it. Internal dimensions - length, big diameter, small diameter - and frequency - and of course a model name to identify it by. That's for flat plate ends. I can do the rounded ends but would need to verify the geometry.
« Last Edit: 06/18/2015 11:33 PM by aero »
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Offline deltaMass

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Perhaps an ASIC accelerator card exists for MEEP?

Online Rodal

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Perhaps an ASIC accelerator card exists for MEEP?
There is not much one can find on that for MEEP because it has such a small user's community (big companies can afford commercial codes).  However, Time-Domain Finite-Element methods have been accelerated using the Graphics Processing Unit, see for example this:
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4168264&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4168264, and the acceleration of a finite difference method like MEEP would be simpler than the one for a Finite Element method. 

However, the authors only claim an improvement of <<a factor of close to two yet, relative to an Intel CPU of similar technology generation.>> so it doesn't come even close to the factors that @aero is talking about.

I think that the best approach is to use a similar finite difference mesh as @aero is using now (just modeling the interior of the cavity and modeling the boundary with boundary conditions) and perform a time-marching finite-difference for the Time-Domain instead of solving the eigenvalue problem.

This would enable us to answer what is the nature of the evanescent waves, and the other questions we have posed.

« Last Edit: 06/19/2015 12:25 AM by Rodal »

Offline aero

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Quote
AERO:
I would be back to the need for a more powerful machine as soon as I increased the computational lattice looking for any RF energy outside of the cavity. (like modeling a screen end, instead of a solid plate) By using a totally enclosed cavity with quarter inch perfect metal skin, I'm not concerned with Meep detecting anything external to the cavity.
snip...

Do you know if MEEP can run under a parallel processing environment, eg will it allow multiple sub processes (multiple parts of itself) to be run concurrently in different locations.

If so I may be able to help you out with the processing load.

Meep sets up the computational lattice as a cuboid which it slices up to run quite well on parallel processor machines. The way it does that is by forming an interface layer between slices which is owned by all adjacent slices. Each processor owns a slice and shares ownership of the adjacent slices which it uses and updates in propagating the fields. Unfortunately, if the interface is not updated the adjacent processors must wait. That works well on multicore machines but as far as I know, there is no way implemented to share an interface with a remote machine.
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Online Rodal

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...The magnetron's microwaves have a negative DC bias, right out of the gun.

http://www.cpii.com/docs/related/2/Mag%20tech%20art.pdf

...
Todd

Numerical Study of Relativistic Magnetrons  (Attached below)
H.W. Chen, C. Chen
December, 1992
Plasma Fusion Center
Massachusetts Institute of Technology
Cambridge, MA 02139 USA

Quote from: H.W. Chen, C. Chen
Although magnetrons are widely used as microwave sources, a fundamental understanding
of the underlying interaction physics is still being developed [7],[9], particularly
in the nonlinear regime.
Much of the theoretical challenge in describing multiresonator
magnetron operation arises from the fact that the electrons emitted from the cathode interact
in a highly nonlinear way with the electromagnetic waves in the anode-cathode gap.
This is manifest through strong azimuthal bunching of the electrons and the formation
of large-amplitude "spokes" in the circulating electron density. In this regard, computer
simulation studies provide a particularly valuable approach to analyze the interaction
physics and nonlinear electrodynamics in magnetrons

Also

A Multiphysics Approach to Magnetron and Microwave Oven Design
https://www.cst.com/Content/Articles/article679/CST_Whitepaper_Magnetron_CST_web.pdf


More on really high power magnetrons and their modeling:

Theoretical Modeling  of an A6 Relativistic Magnetron
http://math.cos.ucf.edu//~kaup/kaup_files/RelMag05.pdf
« Last Edit: 06/19/2015 01:20 AM by Rodal »

Offline aero

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Perhaps an ASIC accelerator card exists for MEEP?
There is not much one can find on that for MEEP because it has such a small user's community (big companies can afford commercial codes).  However, Time-Domain Finite-Element methods have been accelerated using the Graphics Processing Unit, see for example this:
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4168264&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4168264, and the acceleration of a finite difference method like MEEP would be simpler than the one for a Finite Element method. 

However, the authors only claim an improvement of <<a factor of close to two yet, relative to an Intel CPU of similar technology generation.>> so it doesn't come even close to the factors that @aero is talking about.

I think that the best approach is to use a similar finite difference mesh as @aero is using now (just modeling the interior of the cavity and modeling the boundary with boundary conditions) and perform a time-marching finite-difference for the Time-Domain instead of solving the eigenvalue problem.

This would enable us to answer what is the nature of the evanescent waves, and the other questions we have posed.

(just modeling the interior of the cavity and modeling the boundary with boundary conditions)

In that regard, I really really need the complex permittivity of copper at ~2 - 3 GHz. We want to look for evanescent waves which are likely created at the boundaries. But perfect metal may not provide the right "stimulus."
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Offline aero

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I run a test and prototype environment for different parallel processing programs.  I have a small 24 core cluster (6 machines) here beside me but can take over 3 labs to provide 336 cores if required.   I will load meep and have a play.

it will all hinge on task sharing, not thread sharing

You'll likely need to compile from source so get the latest from
https://github.com/stevengj/meep/blob/master/src/meep.hpp#L169-L172
That way your software will be current with the latest documentation.
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Online Rodal

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Perhaps an ASIC accelerator card exists for MEEP?
There is not much one can find on that for MEEP because it has such a small user's community (big companies can afford commercial codes).  However, Time-Domain Finite-Element methods have been accelerated using the Graphics Processing Unit, see for example this:
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4168264&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4168264, and the acceleration of a finite difference method like MEEP would be simpler than the one for a Finite Element method. 

However, the authors only claim an improvement of <<a factor of close to two yet, relative to an Intel CPU of similar technology generation.>> so it doesn't come even close to the factors that @aero is talking about.

I think that the best approach is to use a similar finite difference mesh as @aero is using now (just modeling the interior of the cavity and modeling the boundary with boundary conditions) and perform a time-marching finite-difference for the Time-Domain instead of solving the eigenvalue problem.

This would enable us to answer what is the nature of the evanescent waves, and the other questions we have posed.

(just modeling the interior of the cavity and modeling the boundary with boundary conditions)

In that regard, I really really need the complex permittivity of copper at ~2 - 3 GHz. We want to look for evanescent waves which are likely created at the boundaries. But perfect metal may not provide the right "stimulus."

Why not just start by seeing whether geometrical attenuation is enough to produce them?

Suggestion: take the NASA truncated cone (or any other cone used by the researchers) and using exactly the same cone angle, continue the cone up to the point where the small diameter is 50% of the small diameter used by the researcher (at that point the length of the truncated cone would be extended by approximately the same proportion).   Excite this longer cone at the same frequency as used by the researchers. 

Compare the above geometry (in the Time-Domain) with the interior behavior of the truncated cone used by the researchers.

It will be interesting to see

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