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#2400 by Rodal on 30 Jan, 2016 19:57
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Stupid question:
It is not a stupid question at all
Have someone think about of some kinetic response while heating up the antenna in the first few ms? During the first milliseconds after RF injection the antenna itself acts as a heat sink and causes a divergence of energy applied to the cavitý. Of course this would be a sort of pulse response only.
The back reaction to this energy displacement could cause a kinetic response.. May be this is of the order of 10^-xx.
I am not sure about the relevance at the moment but it came into my mind and I don't wanna withheld this thought
It was actually brought up repeatedly by another NSF user no longer posting at NSF (with a difficult for me to remember username).
The metal walls act as heat sinks. For several modes, like TE01p modes, these heat sinks are predominantly the end plates. In addition you have the antenna(s) acting as heat sinks. Heat escapes either by convection (when operating in air) and radiation (also operating in vacuum) and conduction (also operating in vacuum) through the supports as the resonating cavity is supported during the test, and conduction through the antenna cable.
In addition to induction heating of the walls and induction heating of the antenna, one has dielectric heating: the dielectric insert(s) also heat up (due to their tan delta>0).
Greg Egan's words are most appropriate:Quote from: Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.htmlIf the cavity was surrounded by vacuum, the heat produced would be lost as infrared radiation, giving rise to a back-reaction on the cavity wall. That force would be normal to the wall, so if we neglect the effects of heat conduction in the cavity wall (which could redistribute the intensity of radiation from different parts of the surface) all the calculations would be identical to those we carried out for the internal radiation pressure for the TE modes, and the force would sum to zero. Even if heat conduction destroyed this perfect balance, relativity would put an absolute ceiling of P/c (where P is power and c is the speed of light) on the thrust due to this radiation pressure; this works out at 3.33 micronewtons per kilowatt.
If the cavity is surrounded by air, heat will be lost by conduction into the air. Given the asymmetry of the cavity’s shape and the heat production rate along the wall, there is no reason for the forces due to the air flow to sum to zero.
Here, Greg Egan first considers the heat losses by radiation, the same mechanism responsible for the Pioneer anomaly. Egan correctly concludes that heat by radiation cannot produce a thrust larger than the one of a perfectly collimated photon rocket: force/power = 1/c. After all, such heat is transported by photons through infrared radiation. So, all you have is a photon rocket with photons at infrared frequency and not perfectly collimated.
Second, Greg Egan considers heat lost by convection in air, and correctly concludes that such forces, by convection, can be much larger than the one for a Photon rocket.
However, Greg Egan does not consider heat lost by conduction into supports or the cable connecting to the antennna, and the effect that thermal strains can have on shifting the center of mass as well as thermal stresses can have on anomalous forces (for example, thermal buckling, etc.) -
#2401 by rfmwguy on 30 Jan, 2016 20:23
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Housekeeping notes - we are getting into the # of pages where T7 might be starting...usually Chris B gives me the head's-up. He does like to do it as, or slightly after, a new test is released...or some big emdrive news happens.
If anyone notices something like this before I do, give me a PM. I'll clear it with Chris to start T7...that is all...I now return you to your regularly scheduled program
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#2402 by rfmwguy on 31 Jan, 2016 00:10
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Warning...do not do what this person is doing with a magnetron. This could damage soft tissue, specifically the eyes.
A person in russia, painfully unaware of the dangers of mw radiation, used a magnetron to create plasma in a variety of glass enclosures. It is useful to note the shaping of the plasma as mw from the radome excites the inert gas. Also note the attenuation of plasma in the narrow stem of the bulbs. This is similar to waveguide cutoff, where 2.4 GHz is attenuated when the circular waveguide diameter is too small...aka beyond cutoff frequency.
Again...do not attempt this stunt...the danger should be obvious.
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#2403 by Rodal on 31 Jan, 2016 01:05
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Warning...do not do what this person is doing with a magnetron. This could damage soft tissue, specifically the eyes.
A person in russia, painfully unaware of the dangers of mw radiation, used a magnetron to create plasma in a variety of glass enclosures. It is useful to note the shaping of the plasma as mw from the radome excites the inert gas. Also note the attenuation of plasma in the narrow stem of the bulbs. This is similar to waveguide cutoff, where 2.4 GHz is attenuated when the circular waveguide diameter is too small...aka beyond cutoff frequency.
Again...do not attempt this stunt...the danger should be obvious.
It is not like a waveguide or a cavity resonator because:
1) These are glass bulbs. Glass is not a metal used for the walls in cavity resonators or in waveguides. The boundary condition for microwaves is completely different in a waveguide or in a cavity resonator made of metal because the microwaves will reflect off the metal and only penetrate and decay exponentially within 1 micrometer thickness at 2.4 GHz in copper. In a metal walled cavity resonator, resonance occurs as result of standing waves resulting from reflection of travelling waves being reflected by the metal.
2) Instead of reflecting, in the case of the glass bulb, the microwaves transmit through the glass. What you are seeing is not resonance of microwaves as inside an RF excited cavity resonator or microwave. Instead you are seeing plasma excitation of the gasses inside the glass bulb. You are not seeing microwave resonance as in a waveguide or in a cavity, and therefore you are not seeing attenuation or cutoff of resonance either. -
#2404 by rfmwguy on 31 Jan, 2016 01:13
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Glass will slightly deflect mw energy, not as a true metallic cavity. I disagree about the cutoff. If your logic were used, plasma arcs should fill the narrowed stem, they are obviously attenuated by a narrowed dimension...gas pressure is equallized, only explanation is the shape.
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#2405 by Rodal on 31 Jan, 2016 01:21
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Glass will slightly deflect mw energy, not as a true metallic cavity. I disagree about the cutoff. If your logic were used, plasma arcs should fill the narrowed stem, they are obviously attenuated by a narrowed dimension...gas pressure is equalled, only explanation is the shape.
Plasma excitation of an inert gas in a glass bulb is a different phenomenon than electromagnetic cavity resonance of microwaves, described by different equations and due to a different physical mechanism.
The plasma excitation is confined by the glass not at all because the glass is reflecting microwaves. The reason why the plasma is confined is because the glass confines the gas inside, it is not due to microwaves reflecting off the glass. -
#2406 by rfmwguy on 31 Jan, 2016 01:29
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It is not a precise analogy, but a decent visual. Lots of articles about dielectrics such as glass at radio frequencies. Here's one:
http://www.madsci.org/posts/archives/2010-03/1269002620.Ph.r.html
Plastics are also useful in absorbing/attenuating/reflecting rf. Transparent materials are things like dry wood. -
#2407 by SteveD on 31 Jan, 2016 01:53
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@Rodal
I ran across this paper while you were away. http://arxiv.org/abs/1412.0951 (Quantum reflection of photons off spatio-temporal electromagnetic field inhomogeneities). Would such a quantum reflection allow a photon to deflect without transferring momentum to one of the endplates? -
#2408 by Rodal on 31 Jan, 2016 02:06
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@Rodal
I ran across this paper while you were away. http://arxiv.org/abs/1412.0951 (Quantum reflection of photons off spatio-temporal electromagnetic field inhomogeneities). Would such a quantum reflection allow a photon to deflect without transferring momentum to one of the endplates?
Very interesting paper dealing with quantum vacuum nonlinearity, from a very good research institution. Unfortunately I don't see direct application to the EM Drive experiments because the EM Drive experiments are being conducted with such weak electric fields for whom application of linear Quantum Mechanics should be perfectly fine.
As an example, NASA's experiments have been conducted using from 2 watts to about 10^2 watts of power and all EM Drive experiments have only gone up to about 10^3 watts of power, while the paper deals with much stronger fields, for which nonlinearity takes place: the terawatt-class (10^12 watts) laser and a petawatt-class (10^15 watts) laser.
That's 10^9 to 10^12 times more power than used in EM Drive experiments.
Wouldn't it make more sense to experience Quantum Mechanics nonlinearity, or for something different: a warp field (if one were to be observed) with 10^15 watts rather than with the meager 10^2 to 10^3 watts people are using for their DiY experiments?
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#2409 by Rodal on 31 Jan, 2016 03:01
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Please notice that:
In other words, Minotti writes that the theory used in Minotti's paper is in conflict already with our experimental knowledge of the magnetic field around the Earth, so we already know that the theory discussed in the paper cannot be a good model of reality.
Still, Minotti's mathematical analysis is good and useful, as he obtains an exact solution for resonance of the EM Drive under Maxwell's equations which is even more elegant than Greg Egan's solution. Dr. Frasca (NSF user StrongGR) used Minotti's paper as one of his references for his paper on the EM Drive that we discussed in previous threads:
Einstein-Maxwell equations for asymmetric resonant cavities
Marco Frasca
http://arxiv.org/abs/1505.06917v1
Speaking of Frasca's paper, I've stared at it long enough to convince myself that his calculation is probably correct, but that it is of the second order. That is to say what he has calculated is the asymmetric contribution from the electromagnetic force on the walls of the cavity as distorted by the gravitational dispersion induced into the cavity. It is not the force of the photon dispersion itself.
I really should try to do the dispersion calculation from Minotti's cavity solution one of these days.
This paper http://arxiv.org/abs/0811.3924
The effect of general relativity on hyperbolic orbits and its application to the flyby anomaly
Lorenzo Iorio
(Submitted on 24 Nov 2008 (v1), last revised 17 Jan 2009 (this version, v2))
looks at both the gravito electric and the gravito magnetic effects from General Relativity. They both appear as extremely small, so small that they cannot even explain the flyby anomalies experienced around the Earth. The gravito magnetic effect appears as a correction of order (v/c) while the gravito electric effect is even smaller, of order (v/c)^2
Anyway, it is interesting that the gravito magnetic effect is more important than the gravito electric effect. The gravito magnetic effect is known to the cause of so-called Lense-Thirring precessions of elliptic orbits: https://en.wikipedia.org/wiki/Lense%E2%80%93Thirring_precession
The TE01p modes like TE012 and TE013 favored by Shawyer and Yang have a magnetic field acting in the longitudinal direction of the EM Drive.
According to Newtonian mechanics, the rotation of the Earth makes no difference whatsoever to a spacecraft. The Earth mass is simply treated like a point. However with general relativity, we surprisingly find that the rotation of the Earth exerts a (tiny) force on the spacecraft. -
#2410 by dustinthewind on 31 Jan, 2016 04:00
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...
looks at both the gravito electric and the gravito magnetic effects from General Relativity. They both appear as extremely small, so small that they cannot even explain the flyby anomalies experienced around the Earth. The gravito magnetic effect appears as a correction of order (v/c) while the gravito electric effect is even smaller, of order (v/c)^2
Anyway, it is interesting that the gravito magnetic effect is more important than the gravito electric effect. The gravito magnetic effect is known to the cause of so-called Lense-Thirring precessions of elliptic orbits: https://en.wikipedia.org/wiki/Lense%E2%80%93Thirring_precession
The TE01p modes like TE012 and TE013 favored by Shawyer and Yang have a magnetic field acting in the longitudinal direction of the EM Drive.
According to Newtonian mechanics, the rotation of the Earth makes no difference whatsoever to a spacecraft. The Earth mass is simply treated like a point. However with general relativity, we surprisingly find that the rotation of the Earth exerts a (tiny) force on the spacecraft.
That is interesting so when talking about frame dragging it should be specified if it is gravito magnetic or gravito electric that is being discussed? You mention "gravito magnetic" is of the order of v/c. Is that with respect to the angular velocity of the earth? If the earths small velocity per mass but huge mass could drag space then could light, with a much higher velocity, have comparable if not better drag on space, with a moderate amount of energy?
Maybe, for instance forcing light into a curved path similar to the rotation of earth.
This gravito magnetic frame dragging is akin to light traveling around the earth in one direction faster than it does in the other? Well at least, non-locally.
hmm found this, https://en.wikipedia.org/wiki/Light-dragging_effectsQuote..." and light is also pulled around (to some degree) by the rotation (Lense–Thirring effect)."
Which seems to indicate so. Just not sure of the magnitude light would have on dragging space time as it travels in a circle. Maybe it just requires me considering the equations in the link for Lense-Thirring but this is probably for a sphere shape such as a planet or star. -
#2411 by TheTraveller on 31 Jan, 2016 06:18
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EmDrive verifier program
Glad to announce that:
Dave (rfmwguy)
Shell (SeeShell)
Paul (Star-Drive)
have agreed to be verifiers of my 1st build.
I will supply them, at no cost to themselves, a complete and fully built and tested EmDrive system, minus the 27vdc, 9a PSU (which can be just 2 lead acid car batteries in series) so they can test and verify my claimed >= 20mN force generation. The test system is theirs to keep and assist the further development of their own EmDrive builds.
I'm doing this to not only provide independent verification of what I expect to measure (currently at 2.3mN) but to foster a dynamic EmDrive experimenter community that will ensure the EmDrive technology, the "Shawyer Effect", is never ignored nor doubted again.
If there are others who would like to be involved in the verifier program, please contact me via PM.
Phil -
#2412 by Rodal on 31 Jan, 2016 12:06
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EmDrive verifier program
More thoughts on how to best leverage your efforts, time and money, to achieve your goals.
Glad to announce that:
Dave (rfmwguy)
Shell (SeeShell)
Paul (Star-Drive)
have agreed to be verifiers of my 1st build.
I will supply them, at no cost to themselves, a complete and fully built and tested EmDrive system, minus the 27vdc, 9a PSU (which can be just 2 lead acid car batteries in series) so they can test and verify my claimed >= 20mN force generation. The test system is theirs to keep and assist the further development of their own EmDrive builds.
I'm doing this to not only provide independent verification of what I expect to measure (currently at 2.3mN) but to foster a dynamic EmDrive experimenter community that will ensure the EmDrive technology, the "Shawyer Effect", is never ignored nor doubted again.
If there are others who would like to be involved in the verifier program, please contact me via PM.
Phil
Giving NASA your "complete and fully built and tested EmDrive system" will be good if they get the time and budget to test it. But since NASA has already been testing for years their own version of a Shawyer truncated cone, all this is going to add to their testing program, is perhaps the verification of the ability of a truncated cone cavity without a dielectric insert to produce an anomalous force of 20 mn. Although this distinction (anomalous force as per present NASA EM drive with a dielectric insert vs an anomalous force without a dielectric insert) is of interest to this small community that follows the EM Drive threads at NSF, this distinction may be lost to the general public. What the general public, industry and academia cares about is whether the EM Drive anomalous force can be used for practical uses: whether for space propulsion, or propulsion on Earth (as conceived by Shawyer) or even for power generation.
What would move the needle of public, academic and commercial attention the most would be for you to:
1) Provide your "complete and fully built and tested EmDrive system" to Universities, particularly to Aerospace Departments that have interest, know-how and testing capabilities in space propulsion.
2) Even more important than providing the hardware to achieve your aims, would be for you to personally assist Universities and promote your work on how to get your "complete and fully built and tested EmDrive system" to exceed the 20 mN force and develop it into something useful. So, it would be best to work with a local University in Australia, this would leverage your efforts the best to achieve your aims of developing the EM Drive into something useful and not just a curiosity that a small group of people claim that produces a minuscule thrust while being ignored by academia and the aerospace industry. This is something that Shawyer should have done years ago as well: work with Universities in the UK.
3) If the anomalous force is verified at a University, as you expect to happen, leverage that achievement to work with aerospace companies that have the ability and interest to test the EM Drive in space, where these extremely small forces (if they indeed can be used for their space propulsion) can first be put to use.
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#2413 by Rodal on 31 Jan, 2016 14:30
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...
looks at both the gravito electric and the gravito magnetic effects from General Relativity. They both appear as extremely small, so small that they cannot even explain the flyby anomalies experienced around the Earth. The gravito magnetic effect appears as a correction of order (v/c) while the gravito electric effect is even smaller, of order (v/c)^2
Anyway, it is interesting that the gravito magnetic effect is more important than the gravito electric effect. The gravito magnetic effect is known to the cause of so-called Lense-Thirring precessions of elliptic orbits: https://en.wikipedia.org/wiki/Lense%E2%80%93Thirring_precession
The TE01p modes like TE012 and TE013 favored by Shawyer and Yang have a magnetic field acting in the longitudinal direction of the EM Drive.
According to Newtonian mechanics, the rotation of the Earth makes no difference whatsoever to a spacecraft. The Earth mass is simply treated like a point. However with general relativity, we surprisingly find that the rotation of the Earth exerts a (tiny) force on the spacecraft.
That is interesting so when talking about frame dragging it should be specified if it is gravito magnetic or gravito electric that is being discussed? You mention "gravito magnetic" is of the order of v/c. Is that with respect to the angular velocity of the earth? If the earths small velocity per mass but huge mass could drag space then could light, with a much higher velocity, have comparable if not better drag on space, with a moderate amount of energy?
Maybe, for instance forcing light into a curved path similar to the rotation of earth.
This gravito magnetic frame dragging is akin to light traveling around the earth in one direction faster than it does in the other? Well at least, non-locally.
hmm found this, https://en.wikipedia.org/wiki/Light-dragging_effectsQuote..." and light is also pulled around (to some degree) by the rotation (Lense–Thirring effect)."
Which seems to indicate so. Just not sure of the magnitude light would have on dragging space time as it travels in a circle. Maybe it just requires me considering the equations in the link for Lense-Thirring but this is probably for a sphere shape such as a planet or star.
Very interesting paper by our co-author of the NSF EM Drive paper on EM Drives: Mulletron, who posted it on Reddit: https://drive.google.com/file/d/0B4PCfHCM1KYoWGFTc0N1RWlubXM/view a paper by Forward on the American Journal of Physics, where Forward also discusses the gravito-magnetic effect of Einstein's General Relativity giving a small force to an object due to rotation of a massive object like the Earth (which we discussed in the previous posts).
In this paper Forward also discusses other not well known General Relativity effects that give small forces. Unfortunately, Shawyer's EM Drive geometry and microwave excitation (as presently designed and tested) does not appear as a particularly good way to produce such General Relativity effects.
Forward asks an interesting question: whether there could be a gravitational equivalent material property analogous to the magnetic permeability.Quote from: Robert Forward, AMERICAN JOURNAL OF PHYSICS, Vol. 31, No. 3, 166-170, March, 1963, "Guidelines to Antigravity"In studying analogies between electromagnetism and gravitation, it can be seen that one analogous quantity has not been investigated. This is the gravitational equivalent to the magnetic permeability. Electrical power distribution systems depend upon the anomalously large and nonlinear permeability of iron and other magnetic materials. Since all atoms have spin, all materials will have a gravitational permeability which is different from that of free space.
Rough calculations show that this difference is very small, but experimental investigation may find materials with anomalously large or non-linear properties that can be used to enhance time-varying gravitational fields. Also, since the magnetic moment and the inertial moment are combined in an atom, it may be possible to use this property to convert time-varying electromagnetic fields into time-varying gravitational fields. At present, the only way to search for such materials is to intersperse wedges of material between gravitational wave generators and detectors, such as those described by J. Weber, and look for a change in amplitude or direction of propagation. The first efforts in this direction have been carried out by the Russian workers Braginsky, Rudenko, and Rukman with negative results.
It is obvious that research in the field of gravitation will be very difficult since even the most optimistic calculations indicate that very large devices will be required to create usable gravitational forces. Antigravity, like space travel, will probably have no direct effect on the daily life of the average person. Future progress in the control of gravitation, like all modern sciences, will require special projects large sums of money, men, and energy.
So far, 5 decades after he asked the question, the answer appears to be no, concerning naturally occurring materials, but it is interesting whether one could engineer such properties, as it is only recently, for example that we have embarked in engineering metamaterials for stealth purposes. The problem is that gravitation is such a weak force compared to the electromagnetic force.
Also, Forward correctly notes the need for very large objects (and hence large power) to be able to achieve anything significant, which once again unmasks discussions of General Relativity and other New Physics concerning the EM Drive tests: the energy involved in EM Drive tests appears to be way too small for anything significant (involving General Relativity or nonlinear Quantum Mechanics) could be occurring. EM drive experiments instead of involving particle accelerators or petawatt (10^15 watts) lasers, involve...10^2 to 10^3 watts of power, with conventional materials (copper).Quote from: OnofrioAny possible matching between quantum vacuum and gravitation has been so far frustrated by the difficulty for successful experimental observation of predicted effects, as in the well-known example of Hawking radiation, due to the combined smallness of the universal constant of gravitation and Planck’s constant, and the discussion in this work confirms this state of affairs in terms of experimental observability of the investigated effects.
http://arxiv.org/pdf/1303.5695
Gravitational vacuum polarization phenomena due to the Higgs field
Roberto Onofrio
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
(Dated: March 25, 2013) -
#2414 by StrongGR on 31 Jan, 2016 16:48
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...
5) Dr. Marco Frasca (NSF user StrongGR) was also very interested in these interferometer tests, perhaps he can also give us his recollection
...
What motivated the writing of my paper was the news that people at EW shot a laser beam through a cavity filled with an e.m. field and observed a change in the interference pattern. This is somewhat a different way from the original use of the White-Juday interferometer and far removed from the criticisms by Zen-in. This idea by EW people is really original and worth to be analysed further. Nobody else, as far as I can tell, just did this before. The point of view of general relativity, as I have shown, is that they are right as already the simplest plane wave, as stated in the classical textbook "Gravitation", generates a deformation of space-time. So, if I fill a cavity with an e.m. field this effect should be observable and EW people seems to have shown that this is indeed the case.
From my perspective, that of a physicist, this is already a breakthrough. The reason is that this would be the first time that a gravitational effect could be possibly observed on a tabletop experiment. Extending this to the application case, we are able to form e.m. fields as we like and so, we could in principle form gravitational fields in the way we like: This would open up the way to space-time engineering.
I think that this was the original motivation for Harold White to put all this up: Using a strong e.m. field to act in small regions of space-time. The Alcubierre's idea has the serious drawback to require exotic matter and all the solutions of Einstein equations requiring it are suspect at best. But if you can replace such a kind of strange non-existing matter with a real thing there are possibilities.
Indeed, the possibility to do that, from a mathematical standpoint, can be traced back to a paper of mine published on 2006 (see http://arxiv.org/abs/hep-th/0508246) where I provided the mathematics to do that. This did not exist before and the only people trying to do such kind of studies were Belinski, Khalatnikov and Lifshitz that yielded what was dubbed "BKL conjecture". Indeed, these authors were the first to uncover a strong coupling expansion in general relativity. I have had the luck to be taught general relativity by Vladimir Belinski in person: A great physicist let me say. This was my first course where I was exposed to the matter.
I am awaiting, as most people in this forum, the official publication of results of people at EW. I think they are onto something. Then, NASA should assume an official position and it will be a great moment for everybody I believe. -
#2415 by rfmwguy on 31 Jan, 2016 17:32
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Thanks dr frasca for weighing in on the ew interferometer tests. I like the idea of studying this further. Small scale space time distortions using em could yield small scale forces, which I believe is all we are talking about in this forum. It seems like a worthwhile endeavor and surprises me so few appear to be willing to take on the experimental challenge considering what it could mean. It does not seem like heresy to investigate further.
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#2416 by A_M_Swallow on 31 Jan, 2016 18:47
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Thanks dr frasca for weighing in on the ew interferometer tests. I like the idea of studying this further. Small scale space time distortions using em could yield small scale forces, which I believe is all we are talking about in this forum. It seems like a worthwhile endeavor and surprises me so few appear to be willing to take on the experimental challenge considering what it could mean. It does not seem like heresy to investigate further.
I suspect that the lack of experimentation is due to the universities not having any EM Drives. Now that they can be purchased this will change. -
#2417 by Rodal on 31 Jan, 2016 18:49
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Steve, I want to thank you again for asking your question about the energy density. It is an excellent question.TheTRAVELLER's test: CONTOUR PLOTS COMPARISON OF norm of ELECTRIC FIELD in Decibel scale, EXACT SOLUTION vs. FEKO (Boundary Element Method) model
Continuing the discussion from this message ( https://forum.nasaspaceflight.com/index.php?topic=39004.msg1484568#msg1484568 that followed this message: https://forum.nasaspaceflight.com/index.php?topic=39004.msg1483411#msg1483411 ) regarding calculations of TheTraveller's test, I attach below:
1) The previously shown electric field norm (in Decibel logarithmic scale) contour plot calculated using FEKO Boundary Element Method by IslandPlaya (@ Reddit), correctly identified by SeeShells as mode shape TE013
Nice. Two questions (more proforma than anything else).
1. Any evidence of one or more small areas of extreme energy density (especially around the end plates)? Can this simulation offer an explanation for the observed end plate warping at low levels of rf power?
2. Do each of the lobes contain an equal amount of energy? If not, can you identify which have more or less energy?
1) I have not plotted the energy density. Sounds like a very good idea . Will need to find a little time to write a little code to do it.
..
First of all:
1) Dr. White's Quantum Vacuum theory force depends on the energy density
2) Prof. Minotti's General Relativity derivation of the anomalous force depends on the energy density
This in contrast to the formulations of Yang, Shawyer and others.
Second:
3) Greg Egan shows the energy density distribution for the truncated cone resonator but does not elaborate on the reason why it looks like this for TE013:
4) There is a Wolfram Mathematica Demonstration that shows the electric and magnetic energy densities for the first few modes for a cylinder:
http://demonstrations.wolfram.com/CylindricalCavityResonator/
but it does not show the total energy density.
5) I have calculated energy density for TE013 (TheTraveller's test), it looks like the plot shown by Greg Egan.
6) I will post the results next week which are very interesting, as I have not seen a discussion of this topic, which is relevant as to what is going on in the EM Drive. -
#2418 by SeeShells on 31 Jan, 2016 18:49
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...
5) Dr. Marco Frasca (NSF user StrongGR) was also very interested in these interferometer tests, perhaps he can also give us his recollection
...
What motivated the writing of my paper was the news that people at EW shot a laser beam through a cavity filled with an e.m. field and observed a change in the interference pattern. This is somewhat a different way from the original use of the White-Juday interferometer and far removed from the criticisms by Zen-in. This idea by EW people is really original and worth to be analysed further. Nobody else, as far as I can tell, just did this before. The point of view of general relativity, as I have shown, is that they are right as already the simplest plane wave, as stated in the classical textbook "Gravitation", generates a deformation of space-time. So, if I fill a cavity with an e.m. field this effect should be observable and EW people seems to have shown that this is indeed the case.
From my perspective, that of a physicist, this is already a breakthrough. The reason is that this would be the first time that a gravitational effect could be possibly observed on a tabletop experiment. Extending this to the application case, we are able to form e.m. fields as we like and so, we could in principle form gravitational fields in the way we like: This would open up the way to space-time engineering.
I think that this was the original motivation for Harold White to put all this up: Using a strong e.m. field to act in small regions of space-time. The Alcubierre's idea has the serious drawback to require exotic matter and all the solutions of Einstein equations requiring it are suspect at best. But if you can replace such a kind of strange non-existing matter with a real thing there are possibilities.
Indeed, the possibility to do that, from a mathematical standpoint, can be traced back to a paper of mine published on 2006 (see http://arxiv.org/abs/hep-th/0508246) where I provided the mathematics to do that. This did not exist before and the only people trying to do such kind of studies were Belinski, Khalatnikov and Lifshitz that yielded what was dubbed "BKL conjecture". Indeed, these authors were the first to uncover a strong coupling expansion in general relativity. I have had the luck to be taught general relativity by Vladimir Belinski in person: A great physicist let me say. This was my first course where I was exposed to the matter.
I am awaiting, as most people in this forum, the official publication of results of people at EW. I think they are onto something. Then, NASA should assume an official position and it will be a great moment for everybody I believe.
Thanks for replying and helping to clear up some questions. Your input here is greatly appreciated.
Your paper is one reason I elected to go with the quartz rod through the center of the drive. It allows you to keep plate distance for tune and also will allow you to use the quartz rod to do a highly controlled laser interferometer test negating the need for testing in vacuum or through air.
Shell
Added: I'm currently building the second generation of this drive with the tune chamber and the Quartz rod through the center to test at a TE013 mode.
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#2419 by Rodal on 31 Jan, 2016 18:51
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No, the NASA interferometer experiment only used a laser interferometer, a high dc electric field and separately, a cylindrical resonator which most Universities have, and otherwise are very easy to make. There was no frustum of a cone EM Drive used in the interferometer experiments at NASA. (See: https://forum.nasaspaceflight.com/index.php?topic=39004.msg1485460#msg1485460)Thanks dr frasca for weighing in on the ew interferometer tests. I like the idea of studying this further. Small scale space time distortions using em could yield small scale forces, which I believe is all we are talking about in this forum. It seems like a worthwhile endeavor and surprises me so few appear to be willing to take on the experimental challenge considering what it could mean. It does not seem like heresy to investigate further.
I suspect that the lack of experimentation is due to the universities not having any EM Drives. Now that they can be purchased this will change.
_____________
(*) And the EM Drive is just a truncated cone resonator which is very easy to make: the one at NASA was made by Paul March in his living room.
It was actually brought up repeatedly by another NSF user no longer posting at NSF (with a difficult for me to remember username).