Quote from: dustinthewind on 05/02/2015 08:36 amQuote from: Rodal on 05/01/2015 03:53 pmNot according to Maxwell's linear, isotropic equations.The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_waveThe energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.With all respect, and I am not sure this is much of an issue to point out but I think the model of the waves in the cavity as standing waves may be a bit over-simplified. 1. I think one can look at standing waves as super-imposed traveling waves of opposite direction but this part is likely less significant. 2. Maybe of more significance is the ac power in power lines can be modeled as standing waves but if no one is using power. When power starts being consumed the standing waves begin to travel towards the object consuming the power. The moving bulges of magnetic/electric field can be thought of as transporting power from the power station to the consumer. There should be some traveling of the standing waves bulges from the power supply towards areas of heat loss in the cavity I would assume. I can't say the power dissipated into heat loss is significant but it does seem to buck the perfect standing wave view for me a bit. I do understand on the other hand that it may be a good approximation. In ref to the image above, there is wealth of information buried within the earlier pages of this thread. A more accurate representation of what it looks like inside the cavity is available here:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246Paul March was kind enough to attach the Frustrum modes overview 2A.pdf which has all the mode shapes and characteristics of their test article.So things are a bit more complicated than photons bouncing around like marbles in a can. For example, I know that I can only excite TM212 and TM311 (thanks @Rodal for modeling this) with my little setup at home.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878Paul March has shown clearly in his many posts that there is a clear correlation between mode shape and magnitude and direction of thrust. This is where input from RF Engineers would be extremely valuable.Just food for thought, it is worth going back to page 1 and commenting on the stuff starting there. That way the conversation can keep building on ideas.
Quote from: Rodal on 05/01/2015 03:53 pmNot according to Maxwell's linear, isotropic equations.The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_waveThe energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.With all respect, and I am not sure this is much of an issue to point out but I think the model of the waves in the cavity as standing waves may be a bit over-simplified. 1. I think one can look at standing waves as super-imposed traveling waves of opposite direction but this part is likely less significant. 2. Maybe of more significance is the ac power in power lines can be modeled as standing waves but if no one is using power. When power starts being consumed the standing waves begin to travel towards the object consuming the power. The moving bulges of magnetic/electric field can be thought of as transporting power from the power station to the consumer. There should be some traveling of the standing waves bulges from the power supply towards areas of heat loss in the cavity I would assume. I can't say the power dissipated into heat loss is significant but it does seem to buck the perfect standing wave view for me a bit. I do understand on the other hand that it may be a good approximation.
Not according to Maxwell's linear, isotropic equations.The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_waveThe energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.
...In response to the bold and underlined statements above I was just pointing out that I think we may be losing information by the idea of the standing wave model with out considering the power losses (due heating of the cavity and any propulsion) and the transport of energy by [E^2+B^2] http://hyperphysics.phy-astr.gsu.edu/hbase/electric/engfie.html where the stading wave bulges tend to move towards the areas of consumed energy (heating + sparks + propulsion +ect). I was paralleling it to energy consumption in power lines. There might be some hidden phase relation in here lurking that could suggest em-phase propulsion but that's just speculation. I agree in the line of thinking of what is going on in the cavity as more of a wave model than thinking of them as marbles bouncing inside the cavity. I admit there might be some parallel to the marbles but I don't see it. It is interesting to think that as the wave peaks travel towards the small end of the cavity they are being squeezed but if the wave peaks are traveling towards the larger end they are experiencing expansion. It looks like as a result we see the increased B field near the tight end of the cavity and small B field near the big end. I almost want to think of this squeezing as a form of propulsion in the form of resistance of the traveling of the semi-standing waves as they transport energy to areas of heat loss.
Quote from: Mulletron on 05/02/2015 03:51 pmJust want to run this by the group.I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdfI think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either. The balanced gain and loss stuff came up here. 4th-6th links from top.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie. What's the point of having all that accumulated energy sitting in there static, doing nothing? We need this thing to ride the razor's edge between gain and loss. Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharingSo if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.There's a lot we can learn from that whispering-gallery research cited.http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavitieshttp://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdfI'm openly brainstorming here. Would like some feedback.Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?
Just want to run this by the group.I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdfI think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either. The balanced gain and loss stuff came up here. 4th-6th links from top.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie. What's the point of having all that accumulated energy sitting in there static, doing nothing? We need this thing to ride the razor's edge between gain and loss. Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharingSo if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.There's a lot we can learn from that whispering-gallery research cited.http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavitieshttp://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdfI'm openly brainstorming here. Would like some feedback.
Hey everyone!My name is Kurt Zeller, my colleague Bran Kraft and I are undergraduate Aerospace Engineering students at California Polytechnic State University, San Luis Obispo. (authors of this review: http://www.slideshare.net/KurtZeller/investigation-and-analysis-of-anomalous-electromagnetic-propulsion-devices-41315-46946953 ) We are currently designing an experiment to test a resonant cavity. We have made considerable progress on our own and would like to share our methodology with the forum to gain insight and suggestions before we start purchasing materials. Our primary objective is to demonstrate thrust using a counterbalanced lever. Our secondary objective is to quantify the thrust and make changes to the geometry of the dielectric.We have recently received funding for a copper cavity, PTFE plate, and aluminum beam. This aluminum beam will have a sharp fulcrum welded to the bottom and the ends will be recessed lower than the fulcrum to put the center of mass closer to the balance point. We anticipate the thrust will be larger than the fulcrum's friction but this is still a concern in our experiment. An additional concern is the tension force from the cables that supply power. We plan to fix these cables above the fulcrum with enough slack to negate this issue. We acknowledge the difficulties in accurately obtaining thrust measurements but are mainly attempting to demonstrate thrust before quantifying it. The cavity will be made of C10100 Copper alloy tube with two C11000 copper end plates. A symmetric shape was chosen to minimize complications and cost as well as provide a different cavity geometry for comparison. A PTFE plate will machined into discs of varying thickness that fit adequately at the end of the cylinder. We have access to a VNA from our EE department and will use it to determine the resonant frequencies. We are still awaiting approval for our latest proposal to the Cal Poly committee where we requested $3,500 to rent a 2-3 GHz signal generator, a 50W amplifier, and a spectrum analyzer. We are also planning to implement a matched load to absorb reflected power but are still working with professors to design it. Because these devices are incredibly expensive, we have been researching how to engineer a microwave oven magnetron into the power source. Unfortunately, the relatively constant frequency will limit the number of resonant modes that can be excited unless our cavity length is adjustable. Furthermore, thermal expansion may be a much greater issue at higher power and resonance may be more difficult to maintain. In the event that we are approved funding for the rental equipment we will most likely attempt both setups. We are happy to address questions or concerns and we look forward to any suggestions you may have. We understand Eagleworks is planning a similar experiment and we are hoping to gain more insight into their power delivery system. We would like to thank all the contributors to this forum who have been a great help and inspiration for us throughout this project.
One of the very few (only ?) reported null result (down to sensitivity) with experiment on propellantless device (not em drive type...) was obtained with a fully self contained test article :Null Findings on Electromagnetic Inertia Thruster Experiments using a Torsion Pendulum by Brito, Marini, Galian 2009Knowing how to create and see an EM thrust signature, if there is such a thing, is nice. Designing and conducting the experiment to see no thrust signature if there is none is more scientifically valuable IMHO. And at this stage there appear to be more risks in false positives than in false negatives.
But if there's no thrust when the drive is enclosed and if the thrust is diminished, though still present, in a vacuum (when there is no air to push against), doesn't that suggest that the cavity is spewing particles somehow?
Quote from: squid on 05/02/2015 07:09 pmQuote from: Mulletron on 05/02/2015 03:51 pmJust want to run this by the group.I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdfI think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either. The balanced gain and loss stuff came up here. 4th-6th links from top.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie. What's the point of having all that accumulated energy sitting in there static, doing nothing? We need this thing to ride the razor's edge between gain and loss. Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharingSo if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.There's a lot we can learn from that whispering-gallery research cited.http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavitieshttp://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdfI'm openly brainstorming here. Would like some feedback.Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?Hmmm... See: http://newsoffice.mit.edu/2015/self-accelerating-particles-0120Edit: The self acceleration of photons, on the other hand, is old news. http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
Quote from: lasoi on 05/02/2015 11:30 pmBut if there's no thrust when the drive is enclosed and if the thrust is diminished, though still present, in a vacuum (when there is no air to push against), doesn't that suggest that the cavity is spewing particles somehow?Right, put kilowatts of power into something, it will heat up and start outgassing something fierce. But also do a lot of other things.2.5kW is a LOT of power. If it's all essentially absorbed by the cone, then it gets converted into heat. 2.5kW is like the power output of an oven or like 40 incandescent light bulbs. Especially in a vacuum, you're going to heat up your device to hundreds of degrees. If this gets transferred to the thrust-measuring arm at all (which it likely would), you're going to change the resistance of your strain gauge, thus giving you a false thrust reading.Remember that strain gauges are just copper wire, and so acts just as well as a kind of thermometer. A temperature change (unless super, super carefully canceled out--almost impossible to do if there's a large temperature gradient on the gauge itself) will show up as a change in resistance, just like force will.
However, in 2010, Prof. Juan Yang in China began publishing about her research into EM Drive technology, culminating in her 2012 paper reporting higher input power (2.5kW)
My take:There is a potential gradient formed within the cavity causing one end of the device to fall toward the other. The energy density at each end would differ due to the geometry leaving one side with a slightly higher mass-energy density than the other, creating the gradient.Nathan Rogers
Quote from: jmossman on 04/04/2015 05:54 amYou accurately and completely answered the questions I asked. Unfortunately, I didn't ask my questions very well. http://forum.nasaspaceflight.com/index.php?topic=36313.msg1354235#msg1354235A constant-amplitude standing wave does indeed result in a zero time-average Poynting vector. However, I am questioning your conclusion that a constant-amplitude standing wave accurately represents a real resonator cavity such as the as-tested EM drive frustum. Instead, I would expect a decaying amplitude standing wave to be a more accurate model/plot (as would be derived from a full solution to Maxwell's equations with proper boundary conditions such as non-zero resistance, etc).Once a time-decaying standing wave is used for computation of a time-average Poynting vector, I'm having trouble seeing how the incident and reflected energy can perfectly cancel and become zero. I'll readily admit I may be oversimplifying and/or missing a fundamental concept; it's been a long time since I actually computed time constants for resonant cavities using Maxwell's equations and non-zero resistances.Phrased a bit differently, I believe only excited modes with current/thermal losses in the base plates will significantly weight the direction of the time-average Poynting vector. Each pair of incident/reflected waves would have a larger energy loss at the base plate with the excited E field (and therefore excited currents) than the energy loss at the opposing base plate. For modes with near-zero E fields at the base plate boundaries, each incident/reflected wave pair would have a near equal energy delta regardless of which base plate they came in contact with; the resulting time-averaged direction would be random and magnitude limited by the energy lost in the very first reflection (randomly either the large or small base, with a magnitude very close to zero).I view this Poynting vector discussion to be completely independent of whether Dr. White's QV interactions, or some other classical physics can explain the EM drive anomalous thrust. Just wanted to chime in on a what appeared to be the use of a constant-amplitude standing wave to describe a real-world system. Your earlier observation of a non-zero time averaged Poynting vector seemed like a reasonable statement given that only excited modes with current/thermal losses in the base plates would quickly diverge from the simplified constant-amplitude standing wave model. Regards,JamesJames, thank you for the interesting, thought-provoking discussion. Let's calculate some numbers to estimate what we are discussing.The electromagnetic fields transition from the air or vacuum medium (where they are out of phase by 90 degrees) to the copper over an extremely small distance: a boundary layer. The skin depth for copper at 2 GHz is 1.48 micrometers = 58.2 microinches . When showing the Poynting vector field distribution this distance is infinitesimal compared to the rest of the cavity. In this very small distance inside the copper (1.48 micrometers ) the electromagnetic fields in the copper are out of phase by approximately 45 degrees (due to the high conductivity of copper). For a transverse magnetic (TM) mode, the only electromagnetic field component that is continuous across the vacuum/copper interface is the electric field component tangent to the copper surface. More interestingly (for this thread's discussion due to the significance that the NASA experimenters have placed on the dielectric being responsible for providing the measured thrust) is what happens in the High Density PolyEthylene (HDPE) dielectric polymer insert. Because the dimensions of the dielectric are not negligible compared to the EM Drive's dimension, and the dielectric is not modeled as just a boundary condition.The loss tangent of HDPE is reported to be tan delta = 0.0004Therefore the intrinsic impedance angle isintrinsic impedance angle =(ArcTan[0.0004])/2Therefore, inside the HDPE dielectric the electric and magnetic fields, instead of being out of phase by 90 degrees (as they are in the air or vacuum medium), will be out of phase by:90 - (ArcTan[0.0004])/2 = 89.9998 degreesThis phase angle (89.9998 degrees) will show practically no visual difference with 90 degrees at the resolution of the following image :The Poynting vector inside the HDPE dielectric, instead of having a zero time average, will have the following factor multiplying ExB/mu :Cos[90 - (ArcTan[0.0004])/2]/2 = 0.0000999999940000637 So, inside the HDPE polymer dielectric the Poynting vector has this small magnitude over a period (or multiples thereof).So, the extent of this approximation, for the HDPE dielectric is about 0.01 % (which is negligible in comparison to several other approximations).Now, let's examine what this (very small intensity Poynting vector time average) means, concerning the discussion in this EM Drive.If one were to posit that the EM Drive's thrust is due to the very small magnitude of the time average of the Poynting vector due to these thermal losses (in the HDPE dielectric or in the copper):1) It would mean that there should be more thrust with lower Q. This is the complete opposite of what the experimenters like Shawyer claims (Shawyer claims that the higher the Q, the greater the thrust). Notice that Tan [loss angle] = Tan[ 2 impedance angle ]= 1/Q2) All the equations proposed so far (by Shawyer, McCulloch and @Notsosureofit) have predicted thrust proportional to Q. This is the complete opposite of what such a Poynting vector would predict (it would predict thrust proportional to 1/Q instead), becauseTan delta= 1/Qmeasured Q effective tan delta7320 1.366* 10 ^(-4)22000 4.545* 10 ^(-5)10^6 10^(-7)3) It would mean that experimenters like Shawyer and Fetta are in the completely wrong track pursuing superconducting EM Drives, as superconducting EM Drives would lead to practically no thrust (the opposite of what they claim) because superconducting EM Drives would display practically no heat losses and hence zero time average Poynting vector.4) Considering the HDPE dielectric acting as a sink (energy flowing from the EM Drive towards the HDPE where the energy is dissipated internally in the dielectric polymer due to its tandelta and hence irretrievably lost instead of being reflected), the Poynting vector would be directed towards the HDPE dielectric, that is towards the small base, and hence the EM Drive should experience a recoil force and acceleration towards the big base. This is the opposite direction force found in NASA's experiments with the dielectric. (Recall that NASA Eagleworks found no thrust force with mode TE012 without a HDPE dielectric and that with the HDPE dielectric inserted at the small base they found a force and acceleration directed towards the small base.)
You accurately and completely answered the questions I asked. Unfortunately, I didn't ask my questions very well. http://forum.nasaspaceflight.com/index.php?topic=36313.msg1354235#msg1354235A constant-amplitude standing wave does indeed result in a zero time-average Poynting vector. However, I am questioning your conclusion that a constant-amplitude standing wave accurately represents a real resonator cavity such as the as-tested EM drive frustum. Instead, I would expect a decaying amplitude standing wave to be a more accurate model/plot (as would be derived from a full solution to Maxwell's equations with proper boundary conditions such as non-zero resistance, etc).Once a time-decaying standing wave is used for computation of a time-average Poynting vector, I'm having trouble seeing how the incident and reflected energy can perfectly cancel and become zero. I'll readily admit I may be oversimplifying and/or missing a fundamental concept; it's been a long time since I actually computed time constants for resonant cavities using Maxwell's equations and non-zero resistances.Phrased a bit differently, I believe only excited modes with current/thermal losses in the base plates will significantly weight the direction of the time-average Poynting vector. Each pair of incident/reflected waves would have a larger energy loss at the base plate with the excited E field (and therefore excited currents) than the energy loss at the opposing base plate. For modes with near-zero E fields at the base plate boundaries, each incident/reflected wave pair would have a near equal energy delta regardless of which base plate they came in contact with; the resulting time-averaged direction would be random and magnitude limited by the energy lost in the very first reflection (randomly either the large or small base, with a magnitude very close to zero).I view this Poynting vector discussion to be completely independent of whether Dr. White's QV interactions, or some other classical physics can explain the EM drive anomalous thrust. Just wanted to chime in on a what appeared to be the use of a constant-amplitude standing wave to describe a real-world system. Your earlier observation of a non-zero time averaged Poynting vector seemed like a reasonable statement given that only excited modes with current/thermal losses in the base plates would quickly diverge from the simplified constant-amplitude standing wave model. Regards,James
I showed the fact that boundary conditions for the transverse electric (TE) electromagnetic mode shapes all Poynting vector components vanish at the walls of the EM Drive and the fact that for mode shape TE012 without the dielectric the Poynting vector is self-cancelling. This is consistent with NASA Eagleworks results and supports NASA Eagleworks preference for the transverse magnetic (TM) modes over the transverse electric (TE) modes.
Excellent work posting the Shawyer emails.Question on your test rig. You are aware, according to Shawyer, a non moving EMDrive will not generate any thrust and that it must move to enable thrust to be indirectly measured? Are you planning to use a rotary test?http://www.emdrive.com/EmDriveForceMeasurement.pdfAdditionally his test with a dielectric, resulted in reduced thrust generation.http://www.emdrive.com/iac2014presentation.pdf - page 2Wish you all the best of luck. Would be interested to replicate your device.
Because the thruster is at rest, no force will be measured on the load cell.i.e. F = T-R = 0It therefore appears that a force measurement can only be made in a dynamic environment, ideally by allowing the thruster to accelerate, measuring that acceleration, and then calculating the thrust from T = -Ma.
Please review page 2http://www.emdrive.com/iac2014presentation.pdf Note the use of a dielectric resulted in weaker thrust and in the opposite direction, line 3, to a non dielectric EMDrive, line 4, 5 & 6.This suggest EW may have found a new way to gen thrust, via a dielectric, that appears to work when the test device is fixed/stationary and in the opposite direction to a classic EMDrive.Interesting.