Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1804172 times)

Offline space_britannia

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Apologies if this has already been raised, but this paper on propulsion of a graphene sponge by electron ejection (excited by a laser) has been doing the rounds: http://nextbigfuture.com/2015/05/graphene-sponge-can-absorb-light-and.html

Have any attempts been made to measure an electron plume from the EmDrive? Are the devices building up a charge?

Concerning charge, see this : http://forum.nasaspaceflight.com/index.php?topic=37642.msg1390599#msg1390599

Yang in the quoted section: "regardless whether charge particles are presented within the volume, the surface electromagnetic force can change the momentum within the volume V.>>"

Is there a layman's explanation why this is the case? The graphene foam experiment required electrons emitted into the vacuum to provide the momentum change

Offline Rodal

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(set! fsi 3.87295489E+009)                     ; Drive frequency

Not a lot of CPU time at all. Two to 5 minutes, depending on noise BW.
...

Yes, its the same machine.

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?
That's fantastic, I recall when people where suggesting using a more powerful machine or to do your calculations in the cloud !!!

QUESTION1: Is your solution an eigenvalue (frequency) solution (using the MEEP frequency solver)?

QUESTION2: Can you attempt to also perform  a time -marching solution, to see the time-decaying effect of evanescent waves and other effects that Warp-Tech, Shell and myself are interested in?
(Such a solution will take much more computer time of course, and you will have to use a time step small enough to satisfy stability of the central difference scheme)


I still don't see the motivation for me to re-run calculations for slightly different dimensions and slightly different frequencies for the Flight Thruster, based on unpublished numbers that contradict what Shawyer published (3.85 GHz for the Flight Thruster) but you if you are interested in further exercising MEEP, you could try what TheTraveller is suggesting.  I'm not clear as to what are the dimensions that go with the 3.90.......GHz frequency, you may have to obtain that directly from him. And I am still not clear as to whether the Flight Thruster has spherical ends or flat ends, and all the other questions regarding antenna placement, etc.
« Last Edit: 06/18/2015 03:48 PM by Rodal »

Offline TheTraveller

Cavity Length (m)   big diameter (m)   small diameter (m)

0.1386                     0.2314                    0.1257

Congratulations on making such great progress with MEEP where you can now run 3D models.

Additionally, there is the issue of what the excitation RF frequency was.  In Shaywer's publications, Shawyer gives 3.85 GHz for the Flight Thruster, but in that quotation TheTraveller is saying that External Rf was instead 3.90 GHz?

What excitation frequency did you use for your MEEP 3 D analysis ? (3.85 GHz or 3.90 GHz ?)

How much computer time do these MEEP 3D runs take ?

Are you running them on the same computer that you were using to run the MEEP 2D models ?

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?

According to my SS, your freq is 1.47mm too long in length resonance at TE013, but close enough to work with a variable Rf gen.

As we don't know the Flight Thruster internal dimensions. I calculated a set from the known externals and the latest photo. Emailed them to Shawyer and asked if they were close. He responded by giving me the 3.9003GHz resonance frequency for those supplied dimensions. Had I set the length to 141.3mm instead of 138.6mm, the resonant frequency would have been 3.85GHz as attached.

As for the antenna placement by thought is it should be placed at the side wall point where the equivalent guide wavelength is equal to the actual guide wavelength and be a 1/2 stub antenna at the effective guide wavelength. That way when it radiates, it's wavelength is equal to that at it's insertion point.

Shawyer did a drawing which shows this.
« Last Edit: 06/18/2015 03:47 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline TheTraveller

...
(set! fsi 3.87295489E+009)                     ; Drive frequency

Not a lot of CPU time at all. Two to 5 minutes, depending on noise BW.
...

Yes, its the same machine.

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?
That's fantastic, I recall when people where suggesting using a more powerful machine or to do your calculations in the cloud !!!

QUESTION1: Is your solution an eigenvalue (frequency) solution (using the MEEP frequency solver)?

QUESTION2: Can you attempt to also perform  a time -marching solution, to see the time-decaying effect of evanescent waves and other effects that Warp-Tech, Shell and myself are interested in?
(Such a solution will take much more computer time of course, and you will have to use a time step small enough to satisfy stability of the central difference scheme)


I still don't see the motivation for me to re-run calculations for slightly different dimensions and slightly different frequencies for the Flight Thruster, based on unpublished numbers that contradict what Shawyer published (3.85 GHz for the Flight Thruster) but you if you are interested in further exercising MEEP, you could try what TheTraveller is suggesting.  I'm not clear as to what are the dimensions that go with the 3.90.......GHz frequency, you may have to obtain that directly from him. And I am still not clear as to whether the Flight Thruster has spherical ends or flat ends, and all the other questions regarding antenna placement, etc.

I guess you are having a bad day as you seem to be getting confused.

I supplied my estimated Flight Thruster dimensions to Shawyer and asked him what would be the resonant frequency. He replied 3.9003GHz. So my estimated dimensions were close to those of the Flight Thruster's 3.85GHz but not spot on.

How can you NOT be clear as I have stated this now many times??? It would seem you do not read what I post???

Shawyer has stated the Flight Thruster has Spherical ends and a Q of 50,000. Do you read any of what he has published?

All I see is more hand waving as you seem to be determined to NOT post what your method produces for resonance at my estimated dimensions.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline Rodal

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...

I guess you are having a bad day as you seem to be getting confused.

I supplied my estimated Flight Thruster dimensions to Shawyer and asked him what would be the resonant frequency. He replied 3.9003GHz. So my estimated dimensions were close to those of the Flight Thruster's 3.85GHz but not spot on.

How can you NOT be clear as I have stated this now many times??? It would seem you do not read what I post???

Shawyer has stated the Flight Thruster has Spherical ends and a Q of 50,000. Do you read any of what he has published?

All I see is more hand waving as you seem to be determined to NOT post what your method produces for resonance at my estimated dimensions.
It is a great day in the stock market and I'm multitasking.  No, I have not read everything that Shawyer has published.  Can you please link to Shawyer's publications where he states that the Q is 50,000, that the Flight Thruster has spherical ends ?  [I would like to add those links to the EM Drive wiki] Thank you in advance for the links to such publications.

I understand that you are saying that Shawyer told you that the frequency was really 3.90 GHz instead of what he wrote in his publications (3.85GHz).  That is a difference of only 1 % in frequency.  Why is a 1% difference so important?
« Last Edit: 06/18/2015 04:34 PM by Rodal »

Offline rfcavity

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...
(set! fsi 3.87295489E+009)                     ; Drive frequency

Not a lot of CPU time at all. Two to 5 minutes, depending on noise BW.
...

Yes, its the same machine.

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?
That's fantastic, I recall when people where suggesting using a more powerful machine or to do your calculations in the cloud !!!

QUESTION1: Is your solution an eigenvalue (frequency) solution (using the MEEP frequency solver)?

QUESTION2: Can you attempt to also perform  a time -marching solution, to see the time-decaying effect of evanescent waves and other effects that Warp-Tech, Shell and myself are interested in?
(Such a solution will take much more computer time of course, and you will have to use a time step small enough to satisfy stability of the central difference scheme)


I still don't see the motivation for me to re-run calculations for slightly different dimensions and slightly different frequencies for the Flight Thruster, based on unpublished numbers that contradict what Shawyer published (3.85 GHz for the Flight Thruster) but you if you are interested in further exercising MEEP, you could try what TheTraveller is suggesting.  I'm not clear as to what are the dimensions that go with the 3.90.......GHz frequency, you may have to obtain that directly from him. And I am still not clear as to whether the Flight Thruster has spherical ends or flat ends, and all the other questions regarding antenna placement, etc.

I guess you are having a bad day as you seem to be getting confused.

I supplied my estimated Flight Thruster dimensions to Shawyer and asked him what would be the resonant frequency. He replied 3.9003GHz. So my estimated dimensions were close to those of the Flight Thruster's 3.85GHz but not spot on.

How can you NOT be clear as I have stated this now many times??? It would seem you do not read what I post???

Shawyer has stated the Flight Thruster has Spherical ends and a Q of 50,000. Do you read any of what he has published?

All I see is more hand waving as you seem to be determined to NOT post what your method produces for resonance at my estimated dimensions.

He's not replying to you with the full solution because doing this calculation properly takes time. Both the thinking time and the compute time. You should try to solve some problems with a FEM solver instead of walking out some kludgy guided wavelength thing.

You should be extremely content with the fact that Rodal has continued to reply and be civil with you as 99.9% of the people in the EM measurement industry would have just given up and disappeared once you started pushing clearly wrong computation so aggressively.

Offline TheTraveller

He's not replying to you with the full solution because doing this calculation properly takes time. Both the thinking time and the compute time. You should try to solve some problems with a FEM solver instead of walking out some kludgy guided wavelength thing.

You should be extremely content with the fact that Rodal has continued to reply and be civil with you as 99.9% of the people in the EM measurement industry would have just given up and disappeared once you started pushing clearly wrong computation so aggressively.

Dr Rodal has had several weeks to answer my question. Never realised COMSOL was so CPU intensive.

The "kludgy guided wavelength thing" is not my invention. It is how I was taught to do it and how SPR does it.

Wrong computations? SPR seems to do ok with them. 3 working EM Drives with measured thrust data.

Here is the state of play.

1) My SS, openly available, based on the method SPR uses correctly predicts Flight Thruster resonance.

2) SPRs data to me, based on me estimations, correctly predicts a higher resonance of 3.9003GHz and when I lengthen the cavity a few mm, I get 3.85GHz.

3) Dr Rodal has yet to reply to my measurements, yet does so quickly to others, well to others when there is no known resonant frequency to be measured against. Easy to pop out a number when there is no reference.

4) Now it appears to be tag team effort and others are running interference for Dr Rodals unwillingness to do a simple calc.

Here is what we know:

1) The SPR Flight Thruster is driven by 3.85GHz and produces a range of measured thrust versus power.

2) We don't have it's internal dimensions.

3) We do have 2 external dimensions.

4) We do had a set of estimated internal dimensions I calculated based on the external dimensions and the most recent photo.

5) When I sent those estimated internal dimensions to SPR and asked for the resonant frequency, I was told 3.9003GHz

6) When I put that frequency and estimated dimensions in my SS, it said there was resonance.

7) If I increased the length by a few mms, resonance dropped to 3.85GHz.

I would have thought Dr Rodal would welcome the opportunity to test his method against the SPR method but it would seem he is not eager to do so.

Here is the bottom line. What value is Dr. Rodal's or any other method if it does not generate resonance at the 3.85GHz used by the Flight Thruster?

But of course if you don't believe the Flight Thruster produces the claimed thrust, then all this is just noise to you and trying to work out why classic solutions do not produce the right resonance is also not of any interest as it is a waste of time.
« Last Edit: 06/18/2015 04:52 PM 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 aero

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...
(set! fsi 3.87295489E+009)                     ; Drive frequency

Not a lot of CPU time at all. Two to 5 minutes, depending on noise BW.
...

Yes, its the same machine.

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?
That's fantastic, I recall when people where suggesting using a more powerful machine or to do your calculations in the cloud !!!

QUESTION1: Is your solution an eigenvalue (frequency) solution (using the MEEP frequency solver)?

QUESTION2: Can you attempt to also perform  a time -marching solution, to see the time-decaying effect of evanescent waves and other effects that Warp-Tech, Shell and myself are interested in?
(Such a solution will take much more computer time of course, and you will have to use a time step small enough to satisfy stability of the central difference scheme)

  ... snip ...


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.
Retired, working interesting problems

Offline Chrochne

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Please Mr. Traveller be more civil. I love this debate, but there is no need for this kind of attitude. Dr. Rodal means no harm. In fact this debate has such high standard thanks to him and other scientist. Let get back to the civil side of debate, where we respect each others ideas. Your ideas are great too.With kind regards. Your EmDrive followers.

Offline TheTraveller

Please Mr. Traveller be more civil. I love this debate, but there is no need for this kind of attitude. Dr. Rodal means no harm. In fact this debate has such high standard thanks to him and other scientist. Let get back to the civil side of debate, where we respect each others ideas. Your ideas are great too.With kind regards. Your EmDrive followers.

I have asked many times for the calcs. We need to establish if Dr Rodal's method can actually compute the resonate frequency for the real life Flight Thruster. People are starting to build EM Drives. They need to know their dimensions will achieve resonance or they will see NO THRUST.

Knowing a DIYers dimensions will get resonance with their Rf gen is critical as most have very little ability to change frequency.

We have ONE real world example of internal dimension to resonance frequency, yet no one seems to understand the significance of those SPR supplied numbers. Having Dr Rodal verify his method gives the same value is critical to anyone using his numbers.

If you use dimensions that do not produce resonance you will get NO thrust, then you will stop and the EM Drive will get a bad name.

Of everything you can do, in building a EM Drive, getting dimensions that will produce resonance with your Rf gen is the most critical step. That is why I was SO HAPPY when SPR give me the resonance of my estimated Flight Thruster dimensions, cause I could then verify my SS generated the same result.

I really can't understand why Dr Rodal is not revealing his Flight Thruster resonance frequency. Surely he wants to generate good data, so DIYers can go forward, with faith their Rf generators and frustum dimensions will achieve the resonance he has predicted?
« Last Edit: 06/18/2015 05:20 PM 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 Blaine

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Blaine wrote an hour ago
Okay, this is clearly not working as a reliable method of testing for you guys.  But, do you have another plan? Use oil if you continue with this method.  Apparently, that would help a lot according to Rodal.



movax wrote 7 minutes ago
Yes. We will put it on a swimming platform, stabilized by a ring magnet on the ground an another one under the platform.



What does anyone think of the teams idea? Of his idea?
« Last Edit: 06/18/2015 05:19 PM by Blaine »
Weird Science!

Offline Flyby

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I do not think the baby EMdrive will produce any noticeable results...regardless any damping fluid.

- the input power is way too weak, consequently the output forces are impossible to distinguish from any background noise.

-By reducing the size and going from 2.4 to 24ghz, you also make it very, very sensitive to dimensional imperfections and thermal deformations that can de-tune the cavity

If anything can be learned from prof. Yang experimental  (and Shawyer's) results  then it is that you need to feed the device with a lot of power to obtain a clear noticeable result...
You also need a way to tune the waves to the dimensional properties of the cavity...

I really hope ir. P.Marchal get's green light to informing us on their test results....
For me , it will be a "make or break" event...
IF EagleWorks can't produce "something" credible, then I'll have a hard time to keep hoping it might work... Without noticeable force results,  the dream for easier Human interplanetary travel is over...(well, at least with the EMdrive...)

If the experiments can't be validated soon (let's say, this year), then all the theories about the EMdrive are nothing more then brain gymnastics...
« Last Edit: 06/18/2015 05:59 PM by Flyby »

Offline Rodal

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Blaine wrote an hour ago
Okay, this is clearly not working as a reliable method of testing for you guys.  But, do you have another plan? Use oil if you continue with this method.  Apparently, that would help a lot according to Rodal.



movax wrote 7 minutes ago
Yes. We will put it on a swimming platform, stabilized by a ring magnet on the ground an another one under the platform.



What does anyone think of the teams idea? Of his idea?
Thank you for taking the time to point out using oil instead of water.  He doesn't appear to answer regarding oil.  Perhaps they have some environmental regulations on getting rid of oil in Germany, but I doubt it would be a big problem as everybody loves cars in Germany.  He may also be concerned that the damping factor with oil will be too large and negate any measurement, as just immersing the bracket further in water was enough to considerably dampen the response in this latest test.

Concerning the use of magnets, it is noteworthy that NASA Eagleworks has used magnetic damping exclusively, and they have succeeded in getting much better force vs. time signals (at less than 10 microNewtons in several experiments).

I am not hopeful that they are going to get a clear signal because we have two separate people that have conducted calculations of the force that the EM Drive could produce at a Q of 10,000 or 20,000 and it is less than 5 microNewtons in one calculation and 1 microNewton in the other calculation.  Using magnets for stabilization, and/or oil is going to increase the damping coefficient compared to this latest test in water, which will make it less noticeable.

At this point I would suggest:

1) They should measure the Q of the EM Drive when excited with the RF frequency (they don't need to measure any thrust force to measure the Q).  If they don't have the instruments themselves, they could use the one at the University (of Aachen).  At this point it looks like they are testing without knowing what the quality factor of resonance (Q) is.

2) They should examine the internal surface of the Baby EM Drive (was it sufficiently smooth ?, if not, they should smooth the surface)

3) They should try to conduct an experiment in a partial vacuum to reduce air drag (they don't need to simulate the vacuum of space, all they need is to simulate the much smaller pressure that a jet airplane or an high altitude balloon experiences)

4) They are testing near 24 GHz.  This is the frequency at which ammonia emits (which enabled the first Maser) .  They should read about ammonia MASERS, learn the principles behind it, learn safety procedures for handling ammonia and then they might fill the interior of the cavity with  ammonia to see whether ammonia emission makes any difference in their thrust measurements. 
« Last Edit: 06/18/2015 06:11 PM by Rodal »

Offline SeeShells

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...
(set! fsi 3.87295489E+009)                     ; Drive frequency

Not a lot of CPU time at all. Two to 5 minutes, depending on noise BW.
...

Yes, its the same machine.

There's also the question of where the antenna should be located and should it be excited by Ez (currently) or by Hy components?
That's fantastic, I recall when people where suggesting using a more powerful machine or to do your calculations in the cloud !!!

QUESTION1: Is your solution an eigenvalue (frequency) solution (using the MEEP frequency solver)?

QUESTION2: Can you attempt to also perform  a time -marching solution, to see the time-decaying effect of evanescent waves and other effects that Warp-Tech, Shell and myself are interested in?
(Such a solution will take much more computer time of course, and you will have to use a time step small enough to satisfy stability of the central difference scheme)

snip
That's a great idea Rodal! Please please please. Thanks so much @Aero for what you have added to getting this Genie out of the bottle!
Shell

Offline Rodal

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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....
While including a finite difference mesh outside the EM Drive would be the scientific thing to do (as any propulsion in space that we know of either relies on expulsion of mass/energy from the rocket or the use of external fields (like electrodynamic tethers or the use of solar sails)), in this case, for this thread it would suffice to just model the interior cavity to begin with.

The purpose of such an exercise would be more fundamental in nature.  We would be interested in a number of things aside from assessing whether there is any thrust or not at this point from such a model.

It has to do with the ideas that Todd has been pursuing, that there may be evanescent waves inside the cavity.  I think that several other people in this thread (like me and Shell, for example) would be very interested in you running MEEP with a finite difference discretization just inside the cavity, to ascertain the following:

1) Following the time-marching history of the traveling waves from the RF feed going into the cavity and forming standing waves.  The transient should be very short-lived, as you already showed with a MEEP movie early on.  After the transient is over and you get standing waves in the cavity, what do the waves from the RF feed (with the RF feed ON) look like and where and how do they merge with the standing waves?

2) Are there evanescent waves inside the cavity, mainly near the small end? or just standing waves?

3) If there are evanescent waves, what is their time history?

4) If there are evanescent waves existing simultaneously with standing waves inside the cavity, is there any momentum transfer happening (probably changing with time) between the standing waves and the evanescent waves?

5) Is a distinction between standing waves and evanescent waves determinate or is it diffuse, as Zeng and Fan in their paper maintain that travelling waves in a cone becomes evanescent waves continuously and not abruptly?

6) Can you model the time-varying effect of a magnetron feeding the cavity, as suggested by Todd?

7) Are there DC components on the metal cavity as suggested by Todd? What does the DC field look like?

8) At a later point in time, once we have answers to the above questions, we could pursue opening the outside to the cavity, to explore leaking of evanescent waves to the exterior, etc.

« Last Edit: 06/18/2015 06:58 PM by Rodal »

Offline SeeShells

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Please Mr. Traveller be more civil. I love this debate, but there is no need for this kind of attitude. Dr. Rodal means no harm. In fact this debate has such high standard thanks to him and other scientist. Let get back to the civil side of debate, where we respect each others ideas. Your ideas are great too.With kind regards. Your EmDrive followers.

I have asked many times for the calcs. We need to establish if Dr Rodal's method can actually compute the resonate frequency for the real life Flight Thruster. People are starting to build EM Drives. They need to know their dimensions will achieve resonance or they will see NO THRUST.

Knowing a DIYers dimensions will get resonance with their Rf gen is critical as most have very little ability to change frequency.

We have ONE real world example of internal dimension to resonance frequency, yet no one seems to understand the significance of those SPR supplied numbers. Having Dr Rodal verify his method gives the same value is critical to anyone using his numbers.

If you use dimensions that do not produce resonance you will get NO thrust, then you will stop and the EM Drive will get a bad name.

Of everything you can do, in building a EM Drive, getting dimensions that will produce resonance with your Rf gen is the most critical step. That is why I was SO HAPPY when SPR give me the resonance of my estimated Flight Thruster dimensions, cause I could then verify my SS generated the same result.

I really can't understand why Dr Rodal is not revealing his Flight Thruster resonance frequency. Surely he wants to generate good data, so DIYers can go forward, with faith their Rf generators and frustum dimensions will achieve the resonance he has predicted?
Simply I dislike conflict, I like well meant criticism and honestly I'm doing my own calculations and I'll not post here for fear of coming under attack. This is silly IMHO.

There is so much happening that is unknown at this time within the Fructum that I don't think you or anyone else have the perfect answers to produce the best thrust, period! It's that simple. Is it the highest Q? Is it the RF source? Is it the thickness of the walls? Is it the shape of the Frustum? Is it, is it, is it...??? And the biggie, what method causes the thrust? Until that is defined all this blustering is for naught.

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. This isn't my first merry go around working with very brilliant people.

I thank you for your passion and everyone else here who has a dream and are stuck to this Tar Baby.

Shell

Offline ZuluMoon99

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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.
[/quote]

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?

Offline 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.

Offline SeeShells

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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.

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

Just a thought.

Shell 

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

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