And while on the subject of simulation: Guido Fetta of Cannae tells me that his COMSOL(?unsure) sim predicts a nonzero net Lorentz force for his device. Now, we all learned that no closed system of currents can produce such a net force. There's a paradox. He insists that there are no significant cumulative rounding errors.Anyone have insight into this?

...BOTTOM LINE: I would suggest for experimenters to try 4 different kinds of ends:1) A solid reflecting end (copper or aluminum)2) A conductive wire mesh3) A transparent glass (transparent to microwaves)4) An open end And compare the results. Such tests would be very valuable both for scientific and engineering purposes to understand what is being measured.

Quote from: deltaMass on 05/09/2015 10:09 PMAnd while on the subject of simulation: Guido Fetta of Cannae tells me that his COMSOL(?unsure) sim predicts a nonzero net Lorentz force for his device. Now, we all learned that no closed system of currents can produce such a net force. There's a paradox. He insists that there are no significant cumulative rounding errors.Anyone have insight into this?Yes. Let's remember that the COMSOL FEA solution is the steady state solution showing the spatial distribution of the field. The harmonic (time varying) part of the field is assumed. So, for example, the Magnetic Field shown on the COMSOL output is the spatial distribution of the magnetic field. Now, what is shown as a maximum and what is shown as a minimum is arbitrary, since depending at what time one arbitrarily chooses to display the magnetic field, as the magnetic field varies with time like a harmonic function.Similarly, the Poynting vector is a harmonic function of time, as you point out, well known in the literature, with a frequency which is twice the frequency of the magnetic and the electric field.Although the spatial distribution of the Poynting vector is non-zero at arbitrary points in time, over a whole cycle it sums up to exactly zero, just like the mean of the magnetic and electric fields is also zero.The Poynting vector solution of Maxwell's equations points towards the Big Base half of the time, and points towards the Small Base half of the time.COMSOL will not tell that to the analyst. The FEA analyst is supposed to know that.It is recommended that COMSOL and any other packages (ANSYS MultiPhysics, etc., ABAQUS, ADINA, NASTRAN) should be run by experience FEA analysts.

...Do you know for a fact that Fetta made this elementary blunder, or are you just hypothesising?

Thanks. And we are in violent agreement about the consequences of applying Maxwell.

Quote from: deltaMass on 05/09/2015 11:14 PMThanks. And we are in violent agreement about the consequences of applying Maxwell.How about his friend, the demon?If I pick my waveleghth, design my cavity, and antenna placement, then adjust the phase of the signal such that one end is in a node and the other is riding a crest, both all the time all the time, I would have an unbalance between the two ends???

....Really and truly, this experiment cries out for a space test.

Quote from: deltaMass on 05/10/2015 12:14 AM....Really and truly, this experiment cries out for a space test.There are several people that think the same way (that it cries out for a space test), while there are several other ones that think it would be premature. Since you made a powerful argument for the energy paradox, it would be useful if you could list all the reasons (and what and how should be tested) why a space test should be the next step, as a powerful argument in that direction may help to push the ball rolling...upwards

...And so this third thrust scenario is this:As soon as the EmDrive is free to move, a definite and constant momentum is established and its thrust falls to zero. So far, so good. But given this third thrust scenario is the correct one, what then is expected to happen when we switch off the power?

FYI Arghhhh!Wasted this rare free day chasing constant acceleration transforms til I remembered my own hypothesis is based on negative feedback of the acceleration. (shows what can happen once the bit is in the mouth) Time for a hot tub...

Quote from: deltaMass on 05/10/2015 01:19 AM...And so this third thrust scenario is this:As soon as the EmDrive is free to move, a definite and constant momentum is established and its thrust falls to zero. So far, so good. But given this third thrust scenario is the correct one, what then is expected to happen when we switch off the power?How do you reconcile this with the NASA Tests showing an impulsive force, in the same direction as the movement, which once it reaches the knee of the uprise, after ~2 sec it either stays fairly constant or continues increasing at a much smaller rate?. None of the NASA tests showed a Dirac delta function type of response. None of the NASA tests showed the force decreasing to zero once the EM Drive started to move, on the contrary, the force stayed constant or it increased.

..I'm not aware of any NASA tests on a moving EmDrive. Refs?As for the static force profile, the small residual increase appears to have a slope that matches, to within experimental accuracy, the prevailing thermal drift.

Briefly moving, yes, but constrained from free dynamics - which is what I'm attempting to address in all three thrust scenarios. If the torque balance shows a rectangular pulse (which it largely does, up to thermal drift), this indicates the prompt onset of a constant force. But this arrangement by no means guarantees that the appropriate momentum, per the third thrust scenario, has been established. In fact it guarantees that it has not, since as soon as the torque balances the thrust, the balance ceases to turn and the momentum is zero. And we're back to a situation tantamount to the EmDrive pushing against an immovable wall - i.e. fully static.Recall the third thrust scenario says that the thrust only falls to zero after the appropriate momentum is established.

Quote from: Notsosureofit on 05/10/2015 01:01 AMFYI Arghhhh!Wasted this rare free day chasing constant acceleration transforms til I remembered my own hypothesis is based on negative feedback of the acceleration. (shows what can happen once the bit is in the mouth) Time for a hot tub...“Einstein box” Gedanken experiment first proposed by BalazsN. L. Balazs, “The energy-momentum tensor of the electromagnetic field inside matter,” Phys. Rev. 91, 408-411(1953).for the system’s center of mass to be in the same place in both experiments, it is necessary for the slab in the latter case to have shifted to the right. The difference between the free-space momentum of the pulse and its electromagnetic (or Abraham) momentum is thus transferred to the slab in the form of mechanical momentum, pM, causing the slab’s eventual displacement in a manner consistent with the demands of the Einstein box experiment.http://bit.ly/1DZl2z6Resolution of the Abraham-Minkowski ControversyMasud MansuripurCollege of Optical Sciences, The University of Arizona, Tucson, Arizona 85721[Published in Optics Communications 283, 1997-2005 (2010)]The dielectric insert may be acting as the slab. That produces a solid movement towards the small end according to Balazs, which is what NASA observes. However, the small end of the EM Drive is not open, so doesn't the wave reflect on the small end's copper surface and therefore enters the dielectric again now heading in the direction towards the big end which produces a movement towards the big base? back and forth?