...I assume what you're plotting at the moment is a highly-zoomed snapshot of initial transient behaviour, and that if we zoomed right out we'd see this time averaged apparent thrust average plus and minus to zero and settle to zero asymptotically as time->infinity.
Quote from: phaseshift on 07/30/2015 10:24 pmQuote from: Devilstower on 07/30/2015 09:55 pmWouldn't any theory of EM drive that involves a fourth spatial dimension — one that's not infinitesimal – necessarily place us in ultrahyperbolic spacetime? Which I've always thought was a rather bad spot for physical constructs dependent on consistent laws. That was always my understanding going back to Klein. No extra spatial dimensions for you! Not unless those dimensions are bound in a compact manifold making them about as easy to access as other parts of the multiverse.But hey, I've got my own heresies. I'm still a fan of the idea that dark matter is just probabilistic gravity leakage across branes rather than some invisible stuff in own universe. It notonly seems neater that way, it blows open fun doors in information theory.(Note: this from a guy whose degrees are biology and geology. No one should allow this post to sway their physics opinions one Planck length.)Read up on the Randall/Sundrum theory that places a short finite length dimension between our brane and a gravity brane, attempting to explain why gravity is so relatively weak.I seem to recall Randall had proposed some CERN experiments to watch for momentum being transferred to/from extra dimensions. Does anyone know if those are still on the books?
Quote from: Devilstower on 07/30/2015 09:55 pmWouldn't any theory of EM drive that involves a fourth spatial dimension — one that's not infinitesimal – necessarily place us in ultrahyperbolic spacetime? Which I've always thought was a rather bad spot for physical constructs dependent on consistent laws. That was always my understanding going back to Klein. No extra spatial dimensions for you! Not unless those dimensions are bound in a compact manifold making them about as easy to access as other parts of the multiverse.But hey, I've got my own heresies. I'm still a fan of the idea that dark matter is just probabilistic gravity leakage across branes rather than some invisible stuff in own universe. It notonly seems neater that way, it blows open fun doors in information theory.(Note: this from a guy whose degrees are biology and geology. No one should allow this post to sway their physics opinions one Planck length.)Read up on the Randall/Sundrum theory that places a short finite length dimension between our brane and a gravity brane, attempting to explain why gravity is so relatively weak.
Wouldn't any theory of EM drive that involves a fourth spatial dimension — one that's not infinitesimal – necessarily place us in ultrahyperbolic spacetime? Which I've always thought was a rather bad spot for physical constructs dependent on consistent laws. That was always my understanding going back to Klein. No extra spatial dimensions for you! Not unless those dimensions are bound in a compact manifold making them about as easy to access as other parts of the multiverse.But hey, I've got my own heresies. I'm still a fan of the idea that dark matter is just probabilistic gravity leakage across branes rather than some invisible stuff in own universe. It notonly seems neater that way, it blows open fun doors in information theory.(Note: this from a guy whose degrees are biology and geology. No one should allow this post to sway their physics opinions one Planck length.)
I assume what you're plotting at the moment is a highly-zoomed snapshot of initial transient behaviour, and that if we zoomed right out we'd see this time averaged apparent thrust average plus and minus to zero and settle to zero asymptotically as time->infinity.
Quote from: deltaMass on 07/31/2015 12:04 amI assume what you're plotting at the moment is a highly-zoomed snapshot of initial transient behaviour, and that if we zoomed right out we'd see this time averaged apparent thrust average plus and minus to zero and settle to zero asymptotically as time->infinity.@Rodal:Can you address this time window speculation of mine please?And yes, I do understand that since you're not including sidewall forces, then you will get an apparent net force directed big end forward.
A "time slice" in seconds is what?
Remember Lifters? They drove the woo community nutso with excitement until it was discovered they worked on an ion wind principle. But this didn't prevent every crackpot theorist with internet access chiming in with their pet theories. What is interesting is how these folks responded after it was discovered that the Emperor had no clothes. They didn't. They just walked away, silently, trailing their tattered mathematics behind them. Now, if you have a theory that definitively predicts EmDrive thrust, and it is later shown that no such thrust exists because all measurements are experimental artifacts, what are you going to say about your theory, now clearly wrong? What suddenly changed to make it wrong? - nothing changed in the mathematics! Will we see any post hoc explanations? Will theories be publicly abandoned? Usually this is never the case.In an ideal world, the faulty assumptions are isolated, identified and discussed.
When Quasars were first found one of the earliest theories is that it was extraterrestrial intelligence communications.
Quote from: deltaMass on 07/31/2015 12:18 amRemember Lifters? They drove the woo community nutso with excitement until it was discovered they worked on an ion wind principle. But this didn't prevent every crackpot theorist with internet access chiming in with their pet theories. What is interesting is how these folks responded after it was discovered that the Emperor had no clothes. They didn't. They just walked away, silently, trailing their tattered mathematics behind them. Now, if you have a theory that definitively predicts EmDrive thrust, and it is later shown that no such thrust exists because all measurements are experimental artifacts, what are you going to say about your theory, now clearly wrong? What suddenly changed to make it wrong? - nothing changed in the mathematics! Will we see any post hoc explanations? Will theories be publicly abandoned? Usually this is never the case.In an ideal world, the faulty assumptions are isolated, identified and discussed.You don't need to go to fringe science for that. Physics is littered with mathematical theories proven wrong. Most mathematical theories are eventually proven wrong or if they survive, they only do so as approximations (Newtonian mechanics being a very useful approximation to the ultimate reality). You don't even need to go to mathematical theories.When Quasars were first found one of the earliest theories is that it was extraterrestrial intelligence communications. CTA-102 was catalogued in the early 1960s by the California Institute of Technology [where Sean Carroll teaches], and proposed, in 1963, by N. S. Kardashev in the scientifically conservative Astronomical Journal of the USSR as evidence of a Type Two or Type Three Kardashev civilization. A worldwide sensation followed a TASS agency announcement that Gennady Sholomitskii of the Sternberg State Astronomical Institute, following up Kardashev's idea, had found CTA-102 to be the beacon of a "supercivilization".
@Rodal. OK ~40 ps/timeslice. 2.45 GHz period = 408 ps. So 10 ts/period - probably precisely. It needs to be precise i.e. an integer number of timeslices per period.
Quote from: deltaMass on 07/31/2015 02:06 am@Rodal. OK ~40 ps/timeslice. 2.45 GHz period = 408 ps. So 10 ts/period - probably precisely. It needs to be precise i.e. an integer number of timeslices per period.Your logic is correct. The assumption that the frequency is precisely 2.45 GHz is incorrect.
@SeeShells - https://drive.google.com/folderview?id=0B1XizxEfB23tfms4ZElWR0FXbzZ2a0E0aFkyNE1CTUF0NEwyOUU5amY3aG5BVUw3TldfN0E&usp=sharingSorry, I'm going to need to run it again, this time using a larger lattice with absorbing boundary layers. And figure out how to organize the image files. Putting them all in one big folder doesn't work as you can see.However, this data could be considered to represent the frustum operating in a very small perfect metal box. Energy leaks out through the antenna co-ax connection and bounces all over the place. (kind of like EW testing at ambient with the chamber door closed, only smaller.) I need to absorb the energy before it bounces off the edges of the lattice in order to represent an open test facility. Of course in the real world, your cavity will have other gaps, even if very small, but aren't you planning an open air test?As for data organization, what do you suggest? I have made cuts across the x axis at the big end and small end, and center cuts across the y and z axis for each of 14 time slices and 6 EM field components. I'm inclined to think that 24 folders would be best, each folder containing 14 time slices of one of 6 EM field components for one of the 4 cuts. These are the same cuts that I make for Dr. Rodal's use, and upload in a single file, but of course csv files are not very visual.
Interesting calcs digging through the data of Prof Yang.When her team redid the measurements from the dip in their Force curve, as I reported earlier, they adjusted their data to show a 4N/kW result.http://forum.nasaspaceflight.com/index.php?topic=37642.msg1406672#msg1406672The cavity they used had a measured Q of 1,531 because it needed a wide bandwidth to try to swallow all their magnetrons output. Adjusting the 4N/kW value to a cavity with a Q of 117,500 (their latest design) the Specific Force would grow to 307N/kW. Playing with the cavity Df to get it to 0.95 and still having the 117.500 unloaded Q would maybe boost it another 50%.Then ripping out all cryo cooling, reducing tank sizes, leaving only what is needed to drive the fuel cells, TWTAs & EMDrives, reducing the frame to a non space, non ablative entry airframe, no wings nor tail, the Spaceplane's, now a wingless Drone, mass would probably drop at least 50% to say 5t which would need 50,000N to lift off. Would require 163kW of Rf at 307N/kW, so the existing fuel cells and TWTAs could power the 5t drone.Which suggests it may indeed be possible to build a non superconducting EMDrive powered 5t drone, based on the work already done for the Spaceplane and using the latest Prof Yang high Q cavity design being feed with a narrow band Rf signal that auto tracks cavity resonance changes.As the 5t gross takeoff mass includes 1t of cargo mass, it would not be that hard to put a pilot, a few paxs and cargo in that airframe as the LOx and LH2 tanks will be reduced very significantly as no cryo cooling will be required.Yes I know it is just speculation but the numbers do stack up and numbers that stack up make an engineer's gut happy to say, Yes it may be doable with enough engineering hours and funds.BTW I'm starting to think the Tajmar experiment was meant to provide Shawyer with a low point Q value to add to his Q versus Specific Force chart.
Random thought alert - I respect dead scientists, its just that I expect live ones to take it to the next level
To help in this question it deserves a look the Gerald Kaiser work "Electromagnetic inertia, reactive energy and energy flow velocity" http://iopscience.iop.org/1751-8121/44/34/345206/ and subsequent works by others easy to track in Thomson Reuters WoS....Maybe a good starting point to face EM Drive challenge is to characterize a cavity by irradiating it with wavelets instead of sinusoidal waves... But there is no way to transmit wavelets, unless using a extremely wideband linear amplifier and antenna (fractal antenna?).
...Swirling electromagnetic waves, as with air, could create suction in the direction of the narrow end of the vortex. Thus, I've been reluctant to quantify the force as "thrust". Visualizing what occurs in a non-static frustum lead me to explore some papers on a electromagnetic vortices .Be aware, there are 4th dimensional properties going on here and its not for the faint of heart.Here is one of those papers: http://arxiv.org/ftp/arxiv/papers/1008/1008.3994.pdfMeepers will no doubt have issues with 4th dimensional properties as well as non-steady state EM waves in a Rotational propogation...just what fires naturally out of a magnetron's radome. There you have it. Its where I'll be spending my theory time. Comments and critiques welcomed.p.s. Yes, I know, a Z axis rotation needs to be measured along the longitudinal axis. To date, no one has tried this.