Quote from: Rodal on 06/18/2015 06:54 PMQuote from: SeeShells on 06/18/2015 06:47 PM...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

Quote from: SeeShells on 06/18/2015 06:47 PM...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.

...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. ...

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.

Quote from: SeeShells on 06/18/2015 07:15 PMQuote from: Rodal on 06/18/2015 06:54 PMQuote from: SeeShells on 06/18/2015 06:47 PM...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? ShellI think that's fantastically clever, inventive, imaginative and very original !!!!

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.

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.

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.

Just came across a very interesting paper;http://arxiv.org/pdf/0708.3519.pdfPhotons inside a waveguide as massive particlesZhi-Yong Wang1, Cai-Dong Xiong"In the paper, we show that there exists a close analogy between the behavior of deBroglie 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."

Quote from: WarpTech on 06/18/2015 08:08 PMJust came across a very interesting paper;http://arxiv.org/pdf/0708.3519.pdfPhotons inside a waveguide as massive particlesZhi-Yong Wang1, Cai-Dong Xiong"In the paper, we show that there exists a close analogy between the behavior of deBroglie 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 v_{g} => 0;m_{photon} = h/cλ_{c}and have relativistic momentum;p = m_{photon}*v_{g}/√(1 - (v_{g}/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.pdfI 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)dtIn 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

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

Perhaps an ASIC accelerator card exists for MEEP?

QuoteAERO: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.

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...

...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

Although magnetrons are widely used as microwave sources, a fundamental understandingof the underlying interaction physics is still being developed [7],[9], particularlyin the nonlinear regime. Much of the theoretical challenge in describing multiresonatormagnetron operation arises from the fact that the electrons emitted from the cathode interactin 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 formationof large-amplitude "spokes" in the circulating electron density. In this regard, computersimulation studies provide a particularly valuable approach to analyze the interactionphysics and nonlinear electrodynamics in magnetrons

Quote from: deltaMass on 06/18/2015 11:32 PMPerhaps 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.

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

Quote from: Rodal on 06/19/2015 12:21 AMQuote from: deltaMass on 06/18/2015 11:32 PMPerhaps 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."