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#2600 by Rodal on 06 Nov, 2017 16:23
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My understanding is that they did analyze, design, measure and conduct the experiment such as to remove such DC ground loop currents, but we will have to wait until we can see a formal written published report to assess the effectiveness of their efforts in this regard. Meanwhile, it behooves anybody claiming EM Drive anomalous forces (at a time of their convenience) to (also) test their drive at 90 degrees to the longitudinal orientation.
My 2015 arxiv paper hypothesized that the force measured by EW's 2014 experiment was caused by Lorentz force caused by DC ground loop currents interacting with the Earth's magnetic field, ie, "magnetic needle" effect. I'd suggest the authors of the new experiment to examine and remove DC ground loop currents in their system before they look at magnetic needle effect of the frustum itself.
[conceptual image of an early version of Monomorphic's drive shown with the direction of the measured force at the university, for visualization purposes]
VIEW FROM ABOVE (plane of drawing parallel to ground)
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#2601 by SteveD on 06 Nov, 2017 17:01
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Dr. Rodal I am completely lost here. When you say a perpendicular force has been measured by TU Dresden are you talking about the paper several years ago that mentioned one or some new results from the conference? When you are talking about Jamie's results are you talking about the prior 3W test or new data we have not yet seen.
If TU has new data showing a perpendicular force is that force at 90 degrees from a side injection as you show or at 180 degrees as the first TU paper be several years ago claimed? -
#2602 by tchernik on 06 Nov, 2017 17:48
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My understanding is that they did analyze, design, measure and conduct the experiment such as to remove such DC ground loop currents, but we will have to wait until we can see a formal written published report to assess the effectiveness of their efforts in this regard. Meanwhile, it behooves anybody claiming EM Drive anomalous forces (at a time of their convenience) to (also) test their drive at 90 degrees to the longitudinal orientation.
My 2015 arxiv paper hypothesized that the force measured by EW's 2014 experiment was caused by Lorentz force caused by DC ground loop currents interacting with the Earth's magnetic field, ie, "magnetic needle" effect. I'd suggest the authors of the new experiment to examine and remove DC ground loop currents in their system before they look at magnetic needle effect of the frustum itself.
[conceptual image of an early version of Monomorphic's drive shown with the direction of the measured force at the university, for visualization purposes]
While a potential sad ending, it's indeed a reasonable explanation. The force of the phenomenon is so low it could be explained by many environmental sources of similar magnitude.
Did Dr. Tajmar try to verify if such source of noise was indeed the cause of thrust (e.g. by shielding the device from the magnetic field), of is it still work in progress? -
#2603 by Rodal on 06 Nov, 2017 17:51
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Dr. Rodal I am completely lost here. When you say a perpendicular force has been measured by TU Dresden are you talking about the paper several years ago that mentioned one or some new results from the conference? ...
As I said, I am talking about the results presented last week, in thorough detail, over several presentations (including the PhD students) last week, at the workshop you were inquiring about. The workshop were Monomorphic was scheduled to make a presentation, but he did not attend.
Several years ago they had a Q<50 and now the Q is from 40,000 to 500,000. They have addressed even the torsional balance used in the measurement which now is claimed to have a much lower noise ceiling. A brand new isolation foundation, etc....Did Dr. Tajmar try to verify if such source of noise was indeed the cause of thrust (e.g. by shielding the device from the magnetic field), of is it still work in progress?
They did a very thorough job addressing a number of details that others apparently have not, but it is still a work in progress. Only when they write a formal final report and a peer-reviewed paper it will be finalized. -
#2604 by SteveD on 06 Nov, 2017 18:03
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Dr. Rodal I am completely lost here. When you say a perpendicular force has been measured by TU Dresden are you talking about the paper several years ago that mentioned one or some new results from the conference? ...
As I said, I am talking about the results presented last week, in thorough detail, over several presentations (including the PhD students) last week, at the workshop you were inquiring about. The workshop were Monomorphic was scheduled to make a presentation, but he did not attend.
Several years ago they had a Q<50 and now the Q is from 40,000 to 500,000. They have addressed even the torsional balance used in the measurement which now is claimed to have a much lower noise ceiling. A brand new isolation foundation, etc....Did Dr. Tajmar try to verify if such source of noise was indeed the cause of thrust (e.g. by shielding the device from the magnetic field), of is it still work in progress?
They did a very thorough job addressing a number of details that others apparently have not, but it is still a work in progress. Only when they write a formal final report and a peer-reviewed paper it will be finalized.
And they found a downward movement but no directional movement and now think this is some form of compass (an admittedly plausible explanation involving interaction with an outside field). Might I suggest a very simple test that would help to eliminate error sources that could not produce a downward movement.
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#2605 by Rodal on 06 Nov, 2017 18:06
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No.
And they found a downward movement but no directional movement and now think this is some form of compass (an admittedly plausible explanation involving interaction with an outside field). Might I suggest a very simple test that would help to eliminate error sources that could not produce a downward movement.
As I said they found a "comparable magnitude" force in the perpendicular direction to the force measured in the longitudinal direction. They measured forces along both directions. None of the directions were "downward".
They are using a torsional pendulum that can measure forces only in torsion, so both forces are parallel to the ground.
You have to view my drawing from above and not laterally. The plane of the drawing is parallel to the plane of the ground.
The problem is that you have people here talking about strange theories of reflection at the ends, and other theories to explain the EM Drive that cannot even begin to explain a force in the perpendicular direction.
We have gone from theories that cannot even explain the direction (towards the small end or the large end) of the "force" to now having a force in the perpendicular direction which is in complete and utter conflict with the theories of Shawyer, McCulloch and others.
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#2606 by Bob012345 on 06 Nov, 2017 18:19
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But, besides the theoretical reasons, there is not a single reproducible experiment where someone has been able to extract energy from the Quantum Vacuum.
Consider the following thought experiment:
In the reference frame of a distant observer, outside of a gravity well, looking "down" into it. He sees an atom falling from height h1 to height h2 < h1. In doing so, the atom's oscillation transitions to and from the ground state becomes red-shifted, due to gravitational red shift.
Since the frequency of the atomic oscillations decreased, in the frame of the distant observer, the energy of the oscillator was also decreased;
h*f1 > h*f2
E1 > E2
In falling from h1 to h2, the atom lost energy. In this distant observer's frame, the atom's ground state energy is lower at h2 than it was at h1.
Given this example, and the fact that the ZPF sets the ground state energy of the atom. All Hydro-electric power is essentially extracting energy from the Quantum Vacuum.
If in your view, as I understand it, the ZPF essentially supports all processes, is the field emanating from a charge or even a magnet a propagating field that must be continuously supplied by the ZPF? In other words, in your model is there really a continual flux from the ZPF keeping up appearances even in static situations? Thanks.
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#2607 by PotomacNeuron on 06 Nov, 2017 18:42
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No.
And they found a downward movement but no directional movement and now think this is some form of compass (an admittedly plausible explanation involving interaction with an outside field). Might I suggest a very simple test that would help to eliminate error sources that could not produce a downward movement.
As I said they found a "comparable magnitude" force in the perpendicular direction to the force measured in the longitudinal direction. They measured forces along both directions. None of the directions were "downward".
They are using a torsional pendulum that can measure forces only in torsion, so both forces are parallel to the ground.
You have to view my drawing from above and not laterally. The plane of the drawing is parallel to the plane of the ground.
The problem is that you have people here talking about strange theories of reflection at the ends, and other theories to explain the EM Drive that cannot even begin to explain a force in the perpendicular direction.
We have gone from theories that cannot even explain the direction (towards the small end or the large end) of the "force" to now having a force in the perpendicular direction which is in complete and utter conflict with the theories of Shawyer, McCulloch and others.
Do they know my ground loop paper? From your description and the drawing it sounds like they may have this exact problem in their system. (The drawing did not show that they deliberately isolated their frustum from the beam, a remedy of the groud loop problem) -
#2608 by Rodal on 06 Nov, 2017 18:45
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As I explained, the drawing is NOT from them. As I explained I just took a picture from Monomorphic, and I inserted a vector to explain the direction of the force to the audience here. You have no information whatsoever from this sketch of mine to ascertain whether or not they isolated their frustrum from the torsional arm, or anything else, as it is a drawing from Monomorphic, and nothing to do with them!
Do they know my ground loop paper? From your description and the drawing it sounds like they may have this exact problem in their system. (The drawing did not show that they deliberately isolated their frustum from the beam, a remedy of the groud loop problem)
Their frustum does not have an adjustable constant cross-section at one end, their antenna was in a different place, etc. etc. etc.
As to your paper, I do not know who read or did not read your paper. -
#2609 by Peter Lauwer on 06 Nov, 2017 19:57
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They have much better Q's: 40,000 to 500,000 vs. less than 50 then. ...
500k? Is that possible with conventional (not SC) cavities? -
#2610 by SteveD on 06 Nov, 2017 19:57
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The problem is that you have people here talking about strange theories of reflection at the ends, and other theories to explain the EM Drive that cannot even begin to explain a force in the perpendicular direction.
Huh, my hacked together KISS theory predicted sidewall motion if the device was using side injection or a sidewalls mounted antenna. Did the record an equal force for both endplates and sidewalls? That would seem to indicate the compus hypothesis instead of thrust. -
#2611 by Rodal on 06 Nov, 2017 19:59
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...If TU has new data showing a perpendicular force is that force at 90 degrees from a side injection as you show ...
The EM Drive they made when they were working under the advice of Shawyer was very different.
They do NOT use a side injection waveguide anymore. They now use an antenna.
They have much better Q's: 40,000 to 500,000 vs. less than 50 then. They have excellent resonance now.
Their EM Drive is bigger now (remember that Q scales with geometrical size).
They have very good finite element analysis of the mode shapes now (do you remember what a mess was when the huge waveguide compared to the EM Drive before?). They didn't use an adjustable constant cross-section for the new results that were reported: the construction of the EM Drive now is much better quality and it matches with excellent precision the calculated eigenfrequencies and eigenmodes.
They also reported that the Baby EM Drive tested at TU Dresden did not produce a signal above the noise floor (which was below a microNewton).
No side wall injection ! No waveguide used this time !!!!!!!!!!!!
The problem is that you have people here talking about strange theories of reflection at the ends, and other theories to explain the EM Drive that cannot even begin to explain a force in the perpendicular direction.
Huh, my hacked together KISS theory predicted sidewall motion if the device was using side injection. Did the record an equal force for both endplates and sidewalls? That would seem to indicate the compus hypothesis instead of thrust.
Not the EM Drive they made under advice from Shawyer...
They have much better Q's: 40,000 to 500,000 vs. less than 50 then. ...
500k? Is that possible with conventional (not SC) cavities?
I expressed my skepticism and they replied they were confident about it, but it was up to 500,000 only in a couple of measurements, and with TE0np mode shapes (the mode shapes that have highest Q). More measurements between 40,000 to 100,000.
According to the particle accelerator physics literature Q in the lower hundred thousands has been achieved experimentally before in TE0np mode shapes, it is theoretically possible with the correct geometrical size, but it requires very good exactitude in geometrical shape, placement of antenna, coupling, etc.
There is no doubt from looking at their data that they have gone from embarrasingly low Q (the EM Drive with the huge waveguide made with Shawyer advice more than a year ago) to excellent Q now.
Oh, no magnetron now, solid state, and electronics is placed in torsional beam (addressing the issue found by Yang that defenestrated Yang's results). -
#2612 by WarpTech on 06 Nov, 2017 20:09
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It is important to stay informed...
It would have been preferable if Monomorphic would have been at the workshop to hear this information first hand and to ask further questions, but Todd "WarpTech" was also there, so you could ask WarpTech (if you want to have another viewpoint) on what he heard, and what is his understanding.
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Yes, it was jokingly stated that it's not a thruster, it's a compass. However, quite frankly, Jamie has gone to enormous lengths to get everything onto the thrust balance with a well modeled frustum and a low return loss (high Q). The need for this level of accuracy in the test setup is all dependent upon how much SIGNAL to NOISE he can get out of the thruster. Until he actually does some test runs to see what order of magnitude the thrust from his frustum puts out, he's just wasting time adding more features to his thrust balance. IMO, until we start getting some data and can start to actually see thrust in the mN rather than uN range, we're all just pretending it works.
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#2613 by Peter Lauwer on 06 Nov, 2017 22:02
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TU Dresden reported measuring a "force" of comparable magnitude with the EM Drive's longitudinal axis oriented along the arms of the torsional pendulum: a force perpendicular to the longitudinal axis of the EM Drive: a force parallel to the end walls.
In other words the experiments (which in several cases have resulted in forces in the opposite direction than predicted by theory) are also giving a force perpendicular (!) to the one predicted by theory.
Can you make sense out of that as something that is not an artifact due to external magnetic fields?
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Did they measure this "multi-directional force" with several different resonant modes? Or only with TE-modes?
Are they going to publish soon? Do you know anything about that?
It will make some simple diagnostics more difficult, if not impossible. I mean using different orientations of the frustum is the easiest way to get some idea of whether there is a real anomalous force or it is due to heating or magnetic forces. (Besides using a dummy load i.s.o. the frustum. And wrapping the cavity in heat isolation, like several layers of Al-foil.)
Peter -
#2614 by Rodal on 06 Nov, 2017 22:18
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They reported measuring the existence of the perpendicular force with several eigenmodes, which they can do by varying the eigenfrequency....
TU Dresden reported measuring a "force" of comparable magnitude with the EM Drive's longitudinal axis oriented along the arms of the torsional pendulum: a force perpendicular to the longitudinal axis of the EM Drive: a force parallel to the end walls.
In other words the experiments (which in several cases have resulted in forces in the opposite direction than predicted by theory) are also giving a force perpendicular (!) to the one predicted by theory.
Can you make sense out of that as something that is not an artifact due to external magnetic fields?
...
Did they measure this "multi-directional force" with several different resonant modes? Or only with TE-modes?
Are they going to publish soon? Do you know anything about that?
I don't know when they are going to publish, they are very methodical and they are in no hurry to do it. I understand that one of the things they would like to add is to perform the experiments with Helmholtz coils to isolate the experiment from the external magnetic field.
Again, this is the advantage of attending such a workshop: you get to hear such work first hand, and to thoroughly discuss the data and experiments with the researchers.
I understand that the videos of the presentations, as well as the excellent questions and answers that followed the presentations that took place last week at the Advanced Propulsion Workshop at Aerospace Corporation (El Segundo) (including my presentation) will be available through the Space Studies Institute website (ssi.org) within a few weeks. Just like the videos of the Estes conference are still available at that website.
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#2615 by aero on 06 Nov, 2017 22:22
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Dr. Rodal,
Would you please take a close look, as time permits, at the paper here: https://arxiv.org/pdf/0807.1310.pdf
then tell us whether or not the authors are implying that we should expect a lateral force to be generated along with the longitudinal force? It seems to me to say "yes" but I wonder if sufficient rigor has been applied, and I wonder if their result is applicable to resonant cavities. -
#2616 by Rodal on 06 Nov, 2017 22:44
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Dr. Rodal,
You need an external directional field that can penetrate the walls of the EM Drive to interact with the internal electromagnetic fields, to produce any such force on the center of mass.
Would you please take a close look, as time permits, at the paper here: https://arxiv.org/pdf/0807.1310.pdf
then tell us whether or not the authors are implying that we should expect a lateral force to be generated along with the longitudinal force? It seems to me to say "yes" but I wonder if sufficient rigor has been applied, and I wonder if their result is applicable to resonant cavities. -
#2617 by Ricvil on 07 Nov, 2017 00:03
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My "guess" is:
1- Must exist a coupling with another field to produce thrust, because the electromagnetic field per si is confined. The cadidate field? Gravity.
2- The coupling with gravity probaly result in gravitational waves, because would be more effective to carrier energy and moment this way, but would require a density of energy oscillating inside cavity.
3- Just one electromagnetic mode inside cavity is not able to produce a oscillating density of energy, because with just one mode, the energy is oscillating between electric field and magnetic field, and the result is always a stationary distribuition of energy inside cavity, then only a mixing of at least two major diferent interacting modes would be necessary to produce a oscillating distribuition of energy.
4- These two principal degenerated modes ( same resonant frequency), must have diferent center of mass, and must exchange energy by coupling. This is possible? I think YES.
4.1- Without the end plates, what one has is just a tappered conical waveguide, and it's natural modes (TE and TM) can be expressed by fractionary bessel and legendre functions plus exponential complex in spherical coordinate system.
4.2- With spherical end plates, all is perfect, the equations decouples for each orthogonal coordinate, and the spherical front waves find a easy matching of boundary conditions, and even in the case of existence of degenerated modes, they will not couple at all (they will not interact).
4.3- With flat end plates, one can not decouple the equations ( does not exist a orthogonal coordinate system to match all boundary conditions) , then only modes compatible with a "adiabatic evolution of a cylindrical equivalent mode" will not mixing.
4.4- There is another situation for flat end plates even more sutile, where each flat end can be considered a local deformation of a perfect spherical end, and in this case the "Slater formula" predicts a local change of frequency of a propagation mode, so a mode under cutoff condition for tappered waveguide, may becomes a propagating mode at neighborhood of end plate under favorable frequency conditions, and thus becomes a localized resonance.
5- The localized resonances, explained above, will be evanescent along cavity, then it's center of mass of energy density will tend approach the end plates because of exponential decay, but the decay rate depends of the evanescent mode cutoff frequency by resulting dispersion relations.
6- One can see some this localized resonant modes at Frank Davies Comsol paper of frustum modes, and he calls some of these as "pants modes". My favourite is the "Tx3xx mode".
7- Some times, these localized modes are the same type on each end plate (TM-TM or TE-TE), and some times they are diferent (TE-TM), and some times there is only one localized mode very intense in just one side.
8- I'm interested in the case of two localized mode, because I think they can couple each other by tunneling between the "defects", because in fact at the end plates pratically all modes are presents as evanescent modes to match the boundary conditions, but they are very attenuated along cavity as far they are from the final resonant frequency ditacted by phase matching requirements of all boundary conditions.
9-If two localized resonant modes can couple by tunneling, and one of them can interact with a adequated level of gain of a magnetron, then a kind of asymmetrical dimer can be formed.
10- In a dimer, two resonant systems exchange energy, and in some cases the energy is completaly transfered from one resonant system to the other in a oscillatory fashion, at a very high frequency, and in this cavity scenario with two degenerated localized resonant modes, the result will be a very fast oscillatory center of mass of energy density.
11-A electromagnetic dimer inside the cavity can be an efficient way to generate gravitational waves, but if they can generate a directional thrust, I don't know yet.
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#2618 by TheTraveller on 07 Nov, 2017 00:03
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They have much better Q's: 40,000 to 500,000 vs. less than 50 then. ...
500k? Is that possible with conventional (not SC) cavities?
Hi Peter,
Yes it is possible to achieve a Qu of 500K without going cryo. Not easy but it is doable.
As Dr Rodal indicated, Q is mode related. -
#2619 by TheTraveller on 07 Nov, 2017 00:05
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Dr. Rodal,
You need an external directional field that can penetrate the walls of the EM Drive to interact with the internal electromagnetic fields, to produce any such force on the center of mass.
Would you please take a close look, as time permits, at the paper here: https://arxiv.org/pdf/0807.1310.pdf
then tell us whether or not the authors are implying that we should expect a lateral force to be generated along with the longitudinal force? It seems to me to say "yes" but I wonder if sufficient rigor has been applied, and I wonder if their result is applicable to resonant cavities.
Hi Jose,
That is one way to do it.
