Quote from: leomillert on 07/21/2015 01:02 amThis should also help a bit.http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial#Output_tips_and_tricksI also remember: when in doubt, ask the MEEP mailing list. http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discussAnd how does that help? Tell us why it helps with the problem we have?
This should also help a bit.http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial#Output_tips_and_tricksI also remember: when in doubt, ask the MEEP mailing list. http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Right now, turning off the source after 0.013 microseconds would be much more informative than running Meep up to 1 microseconds and beyond.This is something that Todd asked many days ago: just turning off the source and seeing what happens.
Quote from: aero on 07/21/2015 01:17 amQuote from: leomillert on 07/21/2015 01:02 amThis should also help a bit.http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial#Output_tips_and_tricksI also remember: when in doubt, ask the MEEP mailing list. http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discussAnd how does that help? Tell us why it helps with the problem we have?It tells how to output directly to images instead of h5 files.(run-until 200 (at-every 0.6 (output-png Ez "-Zc bluered")))From that command, it should be possible to discover how to output to csv files, which was, if I understood correctly, what you wanted to do.Maybe output-txt instead of output-png? I don't know, but it's a single command, so it shouldn't be too hard for us to discover it.
QuoteRight now, turning off the source after 0.013 microseconds would be much more informative than running Meep up to 1 microseconds and beyond.This is something that Todd asked many days ago: just turning off the source and seeing what happens.Self sustaining action of some sort? (if only for a fragment of a microsecond)
Quote from: Ricvil on 07/21/2015 01:19 amBeyound a source of microwave, could the magnetron coupled to cavity be acting as a amplifier too?It would be nice to elaborate on that.
Beyound a source of microwave, could the magnetron coupled to cavity be acting as a amplifier too?
...some parameter studies WRT antenna placement and / or geometries could be useful to flesh the EM drive out. We're all missing something ..
Quote from: Rodal on 07/21/2015 01:31 amQuote from: Ricvil on 07/21/2015 01:19 amBeyound a source of microwave, could the magnetron coupled to cavity be acting as a amplifier too?It would be nice to elaborate on that....If the magnetron is acting as a amplifier there is a chance of a effective active load on the cavity, and perhaps some nonreciprocity too.
Quote from: notarget on 07/20/2015 08:52 pm...some parameter studies WRT antenna placement and / or geometries could be useful to flesh the EM drive out. We're all missing something ..RIGHT ON !Agreed 100%
While I have the temerity to vomit-out my ignorant opinion,Its been my sad experience, too often, computers have been a hindrance rather than an asset. Those working in analog electronics know that whatever they calculate, component tolerances and environment, especially around high-Q and high-gain circuits, will need to be physically tuned, so rfmwguy will probably have a working system while others pound on their keyboards. It's really neat the way he can just slide the probe around to find tune. But that won't help elucidate theory. With a loop coupling, the loop can be simply rotated to vary the coupling, to balance cavity Q vs. power supplied.However, even a battery powered, low-power oscillator driving a frustrum, with probes at various points, can measure amplitude and phase fluctuations of a moving frustrum to validate/refute Shawyer's claims about the behavior (although not reaction force or thrust) of his system. And it won't cause near (like say, 10^5) as much thermal detuning, neither oscillator or cavity. Saw and dielectric resonator are available cheap for 900MHz & 2.5 GHz.That would be a relatively simple and safe experiment to acquaint oneself with the technology and art before attempting to use a deadly magnetron or expensive and fragile semiconductor amplifier, which could easily cause big trouble if not shielded adequately.
Should allow a nice static test and coupled with the USB spectrum analyser.http://www.ebay.com/itm/281744660852?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Give should give me a fine real world low power test. Data that we can use to fine tune meep and at least compare.
Yes, "write your own functions" is certainly the Meep way to do things. Although that carried to the extreme would be why bother with Meep, just write your own Meep At the moment what I see is that (really the only ?) new important thing I see with Meep vs the steady-state standing wave solution is the influence of the antenna RF feedThe stress at the opposite end of the antenna is what one sees in the standing wave solution. What gets modified is the stress at the base near the antenna and the whole field near the antenna. (Also the Poynting vector field near the antenna gets modified)I expect that by turning the RF feed OFF we will see the standing wave solution (just at a lower intensity because it is so early in the process after 0.013 microseconds).Since the only new thing I see coming from Meep transient analysis is the antenna, it would be most important to model:1) Different antenna locations (being done)2) Different antennas (monopoles, loop, etc.)3) A Magnetron [all kinds of things here -- just see the post above by Ricvil, besides the obvious one of the Magnetron bandwidth, the Frequency, Amplitude and Phase modulation provided by the magnetron, etc.]4) A waveguide feed (as used by Yang -- who used a waveguide feed instead, and reported the highest force)All of this is more important IMHO, than running Meep to steady-state. I agree with Todd.Todd, where are you ? we miss you
Quote from: Rodal on 07/21/2015 02:08 amQuote from: notarget on 07/20/2015 08:52 pm...some parameter studies WRT antenna placement and / or geometries could be useful to flesh the EM drive out. We're all missing something ..RIGHT ON !Agreed 100%If I might be pardoned for butting in, the simulations so far, while very important to familiarize with the software, don't inspire my confidence WRT utility.Why not follow conventional industry wisdom using conventional E-field probe, H-field loop, or aperture methods of excitation, similar to Shawyer, White or Yang? For instance, see:http://www.scribd.com/doc/111892661/Waveguide-Theory pg. 10 on coupling methods.That short document has pretty pictures, the pretty equations are in the MIT Radiation Lab series.A big 'ol dipole thrown in anywhere probably will trash the Q of the cavity.Rfmwguy has the right idea, I think, in putting the probe 1/4 wave from the wall, but what is the impedance at that point?I've been perusing documents lately, but I got mpd installed (it can be called by meep) because I think the methodology to follow is to calculate the modes using a fast harmonic solver (mpd), plot the cavity Z and Vg (E/B), calculate the Q and other nearby modes, then - Use the eigenvalue mode of interest to excite the cavity in the time-domain (meep) and see what it does when the cavity is accelerated. I believe meep can do this. I read a post on the meep mailing list where the Cerenkov effect was being modeled by moving the charge-source between runs. Why not the cavity? Something I hope to look into.Because Shawyer somewhat obscurely, in a couple documents states that motion is necessary to produce thrust. Since we're considering his cone, why not his important precondition for its operation?The cone is an impedance gradient; as Frobnicat points out, equivalent to gravity or an accelerated inertial frame.If the cone is accelerated, it "straightens out" the cavity, affecting field/energy/momentum distribution, and delta-momentum means a change in force inside the frustrum. The antenna is bolted to the inertial frame of the cone, but with a Q of 10k, there is 10^4 times more stale energy than fresh energy to apply force to an accelerating frustrum.Its great to have newcomers with hardware. Let's not waste this great opportunity! I wish I had more experience with EM and waveguides. We could really use some expert advice. Microwave circuits have been called a "black art" for a reason.
http://www.scribd.com/doc/111892661/Waveguide-Theory pg. 10 on coupling methods.
...Reading Woodwards description of transient mass fluctuation, makes it sound very similar to what is being discussed here. Is there a possibility that all of standing waves and power being pumped into the copper fulstrum is making it mimic one of Woodwards capacitors? Would provide a (relatively) clean way to try to tie the effect back into the realm of accepted physics. But again, I may just be oversimplifying it.