You know you the got EmDrive fever when you wake up at 3am and stare at mode shapes for two hours playing "spot the quadrupole moment". Based on previous discussions about the possibility of photons becoming massive while confined within waveguide and resonators, assuming this to be true, then the deformation of these resonant modes by virtue of the cavity geometry should produce mass quadrupole moments all over the place. For instance, if I had a resonant sphere, I would have no quadrupole moment. QuoteThe quadrupole represents how stretched-out along some axis the mass is. A sphere has zero quadrupole. A rod has a quadrupole. A flat disk also has a quadrupole, with the opposite sign of the quadrupole of a rod pointing out from its flat sides. The rod is a sphere stretched along that axis and the disk is a sphere squashed along that axis. In general, objects can have quadrupole moments along three different axes at right angles to each other. (The quadrupole moment is something called a tensor.)https://van.physics.illinois.edu/qa/listing.php?id=204So yeah, I'm squashing massive spheres here at 5:25 in the morning and not really sure if this makes any sense. Is this the definition of pathological science? Also thanks to @Rodal for offline discussion about TM212 vs TE012.
The quadrupole represents how stretched-out along some axis the mass is. A sphere has zero quadrupole. A rod has a quadrupole. A flat disk also has a quadrupole, with the opposite sign of the quadrupole of a rod pointing out from its flat sides. The rod is a sphere stretched along that axis and the disk is a sphere squashed along that axis. In general, objects can have quadrupole moments along three different axes at right angles to each other. (The quadrupole moment is something called a tensor.)
Quote from: Mulletron on 01/18/2016 03:33 amYou know you the got EmDrive fever when you wake up at 3am and stare at mode shapes for two hours playing "spot the quadrupole moment". Based on previous discussions about the possibility of photons becoming massive while confined within waveguide and resonators, assuming this to be true, then the deformation of these resonant modes by virtue of the cavity geometry should produce mass quadrupole moments all over the place. For instance, if I had a resonant sphere, I would have no quadrupole moment. QuoteThe quadrupole represents how stretched-out along some axis the mass is. A sphere has zero quadrupole. A rod has a quadrupole. A flat disk also has a quadrupole, with the opposite sign of the quadrupole of a rod pointing out from its flat sides. The rod is a sphere stretched along that axis and the disk is a sphere squashed along that axis. In general, objects can have quadrupole moments along three different axes at right angles to each other. (The quadrupole moment is something called a tensor.)https://van.physics.illinois.edu/qa/listing.php?id=204So yeah, I'm squashing massive spheres here at 5:25 in the morning and not really sure if this makes any sense. Is this the definition of pathological science? Also thanks to @Rodal for offline discussion about TM212 vs TE012.In this view, the distortion of the confined wavefunction by the cavity is relieved by acceleration. (in the direction which generates the opposite distortion) This is the source of the increase in entropy.Still looking at the behavior under acceleration as opposed to the static force, ie. the force of the distorted wavefunction trying to restore itself. Each contribution examined so far has reduced the force as acceleration increases.
Quote from: Notsosureofit on 01/18/2016 11:45 amQuote from: Mulletron on 01/18/2016 03:33 amYou know you the got EmDrive fever when you wake up at 3am and stare at mode shapes for two hours playing "spot the quadrupole moment". Based on previous discussions about the possibility of photons becoming massive while confined within waveguide and resonators, assuming this to be true, then the deformation of these resonant modes by virtue of the cavity geometry should produce mass quadrupole moments all over the place. For instance, if I had a resonant sphere, I would have no quadrupole moment. QuoteThe quadrupole represents how stretched-out along some axis the mass is. A sphere has zero quadrupole. A rod has a quadrupole. A flat disk also has a quadrupole, with the opposite sign of the quadrupole of a rod pointing out from its flat sides. The rod is a sphere stretched along that axis and the disk is a sphere squashed along that axis. In general, objects can have quadrupole moments along three different axes at right angles to each other. (The quadrupole moment is something called a tensor.)https://van.physics.illinois.edu/qa/listing.php?id=204So yeah, I'm squashing massive spheres here at 5:25 in the morning and not really sure if this makes any sense. Is this the definition of pathological science? Also thanks to @Rodal for offline discussion about TM212 vs TE012.In this view, the distortion of the confined wavefunction by the cavity is relieved by acceleration. (in the direction which generates the opposite distortion) This is the source of the increase in entropy.Still looking at the behavior under acceleration as opposed to the static force, ie. the force of the distorted wavefunction trying to restore itself. Each contribution examined so far has reduced the force as acceleration increases.You mean like Pound-Rebka?https://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experimentBy the equivalence principle, it'd be the same thing for an EmDrive accelerating. Are you looking for an expression to show where the cavity would fall out of resonance while accelerating?
A solution to the acceleration limitation of superconducting EmDrive engines has been found.
Shawyer mentions on his website QuoteA solution to the acceleration limitation of superconducting EmDrive engines has been found. but he calls it a doppler shift... I'm still looking around on his website for the "solution" but since superconducting=high Q, any frequency shifts could kill cavity resonance depending on how narrow the cavity bandwidth actually is.
Motivation alert - While some may be discouraged by the lack of any new info on emdrive, there is a "noble" reason to continue the search for new propulsion...while it may take decades, if we never start the race, we'll never finish it. So, I give you yesterday's video link to the barge landing yesterday of SpaceX's Falcon 9. Carrying heavy propellant does have its disadvantages:http://www.space.com/31653-spacex-rocket-landing-crash-droneship-video.html
Quote from: Mulletron on 01/18/2016 02:27 pmShawyer mentions on his website QuoteA solution to the acceleration limitation of superconducting EmDrive engines has been found. but he calls it a doppler shift... I'm still looking around on his website for the "solution" but since superconducting=high Q, any frequency shifts could kill cavity resonance depending on how narrow the cavity bandwidth actually is.Read his last 3 papers.Roger goes into some detail on how acceleration interacts with high Q cavities and the multiple methods they developed to deal with the effects.
Quote from: SeeShells on 01/18/2016 02:23 am...This was just posted on the other site. Things are now making a little more sense.QuoteSome quick notes.The movies are mislabelled.The TE01 mode should be TE10. It is not any reference to the frustum, but the dominant mode of the waveguides that are excited by the RF source. I should have not have mentioned the rectangular waveguide mode, it is confusing.The Feko solver I'm using is method of moments.The E-field magnitudes shown are not taken on the surface of the frustum (Where they are zero) but 2mm inside.Feko calculates the standing waves. The animation in these movies are made my changing the phase of the RF sources so affecting the instantaneous E-field magnitude displayed. At 2.47 Ghz, this would be pretty fast!The frustum walls are perfect conductors.Note that the E-field scale is logarithmic. This can be misleading or helpful, I'm not sure. Will maybe try a linear scale next time.I'll do an update with an improved model using copper and S-port measurements soon.End QuoteNo, it that does not make any sense There is no such thing as mode shape TE10 n in TEmnp can never be zero. n can only be 1,2,3, etc. (*)I already showed in https://forum.nasaspaceflight.com/index.php?topic=39004.msg1477698#msg1477698 that the mode shape looks like TM112. (**)1) The tangential electric field parallel to a metal wall must be zero, it can never be non-zero2) The quantum number "n" in modes TEmnp or TMmnp can never be zero, it must be equal to or greater than 1. There is no such thing as a mode TE10 !!!!!______________________(*) TE10 would mean that you have a wave-pattern in the circumferential direction but constant field in the radial direction, which is an obvious impossibility.(**) It doesn't look like TE11p either. (At least there is such a thing as mode shape TE11p)
...This was just posted on the other site. Things are now making a little more sense.QuoteSome quick notes.The movies are mislabelled.The TE01 mode should be TE10. It is not any reference to the frustum, but the dominant mode of the waveguides that are excited by the RF source. I should have not have mentioned the rectangular waveguide mode, it is confusing.The Feko solver I'm using is method of moments.The E-field magnitudes shown are not taken on the surface of the frustum (Where they are zero) but 2mm inside.Feko calculates the standing waves. The animation in these movies are made my changing the phase of the RF sources so affecting the instantaneous E-field magnitude displayed. At 2.47 Ghz, this would be pretty fast!The frustum walls are perfect conductors.Note that the E-field scale is logarithmic. This can be misleading or helpful, I'm not sure. Will maybe try a linear scale next time.I'll do an update with an improved model using copper and S-port measurements soon.End Quote
I hope this explains that if you feed RF into a frustum using a rectangular waveguide then the waveguide excitation has to be TE10 (at this freq.)What the heck is happening in the frustum I don't know, but is the whole point of these sims.
It is not any reference to the frustum, but the dominant mode of the waveguides that are excited by the RF source. I should have not have mentioned the rectangular waveguide mode, it is confusing.The Feko solver I'm using is method of moments.
On the discussion on propagation, fields or modes within a cavity or waveguide. Quick and sweet, at the vets trying to work on a cheap tablet.Shellhttps://www.cst.com/Academia/Examples/Hollow-Rectangular-WaveguideA hollow waveguide is a transmission line that looks like an empty metallic pipe. It supports the propagation of transverse electric (TE) and transverse magnetic (TM) modes, but not transverse electromagnetic (TEM) modes. There is an infinite number of modes that can propagate as long as the operating frequency is above the cutoff frequency of the mode. The notation TEmn and TMmn are commonly used to denote the type of wave and its mode, where m and n are the mode number in the horizontal and vertical directions respectively. The mode with the lowest cutoff frequency is called the fundamental mode or dominant mode. For a hollow rectangular waveguide the dominant mode is TE10 and its E, H and J fields are shown in Fig. 2.https://archive.org/stream/ClassicalElectrodynamics/Jackson-ClassicalElectrodynamics#page/n273/mode/2upI've got to take my little Great Pyrenees in to be spade this morning and will be back on later.Shell
Quote from: SeeShells on 01/18/2016 11:39 amOn the discussion on propagation, fields or modes within a cavity or waveguide. Quick and sweet, at the vets trying to work on a cheap tablet.Shellhttps://www.cst.com/Academia/Examples/Hollow-Rectangular-WaveguideA hollow waveguide is a transmission line that looks like an empty metallic pipe. It supports the propagation of transverse electric (TE) and transverse magnetic (TM) modes, but not transverse electromagnetic (TEM) modes. There is an infinite number of modes that can propagate as long as the operating frequency is above the cutoff frequency of the mode. The notation TEmn and TMmn are commonly used to denote the type of wave and its mode, where m and n are the mode number in the horizontal and vertical directions respectively. The mode with the lowest cutoff frequency is called the fundamental mode or dominant mode. For a hollow rectangular waveguide the dominant mode is TE10 and its E, H and J fields are shown in Fig. 2.https://archive.org/stream/ClassicalElectrodynamics/Jackson-ClassicalElectrodynamics#page/n273/mode/2upI've got to take my little Great Pyrenees in to be spade this morning and will be back on later.Shell
Quote from: SeeShells on 01/18/2016 03:55 pmQuote from: SeeShells on 01/18/2016 11:39 amOn the discussion on propagation, fields or modes within a cavity or waveguide. Quick and sweet, at the vets trying to work on a cheap tablet.Shellhttps://www.cst.com/Academia/Examples/Hollow-Rectangular-WaveguideA hollow waveguide is a transmission line that looks like an empty metallic pipe. It supports the propagation of transverse electric (TE) and transverse magnetic (TM) modes, but not transverse electromagnetic (TEM) modes. There is an infinite number of modes that can propagate as long as the operating frequency is above the cutoff frequency of the mode. The notation TEmn and TMmn are commonly used to denote the type of wave and its mode, where m and n are the mode number in the horizontal and vertical directions respectively. The mode with the lowest cutoff frequency is called the fundamental mode or dominant mode. For a hollow rectangular waveguide the dominant mode is TE10 and its E, H and J fields are shown in Fig. 2.https://archive.org/stream/ClassicalElectrodynamics/Jackson-ClassicalElectrodynamics#page/n273/mode/2upI've got to take my little Great Pyrenees in to be spade this morning and will be back on later.ShellThe mode shape TE10 can exist in a rectangular waveguide (because in a rectangular waveguide the lateral dimensions have equal importance, so you can have TE01 or TE10). There cannot be such thing as a "TE10" mode for a cylindrical waveguide or for a conical waveguide. The reason for this is that in a cylindrical or a conical waveguide, "n" stands for the quantum number in the radial direction, and that "n=0" would mean a constant waveform in the radial direction, which is absolutely impossible to occur unless the electromagnetic fields are zero everywhere in the cylinder.
...Correct. Digging this early morning through Jackson's and the web I found that out too.You image looks like a TM112 in the cavity but it shouldn't be. Need to think on this a bit.
Quote from: rfmwguy on 01/18/2016 02:36 pmMotivation alert - While some may be discouraged by the lack of any new info on emdrive, there is a "noble" reason to continue the search for new propulsion...while it may take decades, if we never start the race, we'll never finish it. So, I give you yesterday's video link to the barge landing yesterday of SpaceX's Falcon 9. Carrying heavy propellant does have its disadvantages:http://www.space.com/31653-spacex-rocket-landing-crash-droneship-video.htmlThere was a time when such concerns did not deter engineering studies of much more powerful space propulsion , performing actual testing with conventional explosives to test the concept (instead of microNewton testing) (look at 8 min, for example), and famous physicists like Freeman Dyson were intimately involved:20 Astronauts, all-up mission. Return time from Mars: 42 days. Mars surface payload: 150 metric tonshttps://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
...The interesting thing is that, from all indications, the ORION would actually have worked and would have opened up large scale human interplanetary travel. It would also have had the unfortunate side effect of producing nasty EMPs and wide scale dispersion of radionucleotides.
Quote from: Prunesquallor on 01/18/2016 04:20 pm...The interesting thing is that, from all indications, the ORION would actually have worked and would have opened up large scale human interplanetary travel. It would also have had the unfortunate side effect of producing nasty EMPs and wide scale dispersion of radionucleotides.In comparison with the EM Drive, Orion, although "very difficult to test" because it involved the release of radiation in the atmosphere, it was actually tested (using conventional explosives) and a famous physicist like Freeman Dyson was involved, while the EM Drive is being only researched in labs under 1 milliNewton forces for over a decade, with never-ending discussions about whether the results are thermal and electromagnetic experimental artifacts. Canane and Shawyer (the "S" actually stands for Satellite) discussed testing the EM Drive in Space but it has never actually been done...
Einsteins paper...posted elsewhere, linked here as well. A cylinder in space and imparted motion due to radiation applied:http://einsteinpapers.press.princeton.edu/vol2-trans/214?ajax
Quote from: rfmwguy on 01/18/2016 07:13 pmEinsteins paper...posted elsewhere, linked here as well. A cylinder in space and imparted motion due to radiation applied:http://einsteinpapers.press.princeton.edu/vol2-trans/214?ajaxThis was precisely the point made by NSF user WarpTech, (Todd we miss ya ) in classic exchanges he had in these threads with NSF user DeltaMass (we miss you too ). Unfortunately the EM Drive's claimed self-acceleration does not appear to be explainable on this basis because of...the relatively puny energy change involved in the EM Drive cannot be used to justify the claimed "anomalous force" (off by orders of magnitude...)Back to the whiteboard and keep your eyes on the Notsosureofit hypothesis, who remains here (from time to time )...