Author Topic: EM Drive Developments Thread 1  (Read 795487 times)

Offline Rodal

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Re: EM Drive Developments
« Reply #1160 on: 09/30/2014 01:20 AM »
Sheeesh Hardy har har.  I thought that this was the EM Drive Developments thread.

Fixed that for ya.  But you're right.  Back to regular programming.

[Got more where that one came from.  Just sayin'.]
Hardy har har?  Back to regular programming?  You took the wrong turn?


« Last Edit: 09/30/2014 01:22 AM by Rodal »

Offline ThinkerX

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Re: EM Drive Developments
« Reply #1161 on: 09/30/2014 01:29 AM »
Quote
Here I attach slides 27, 28 and 29

Notice how the expected axion coupling increases with expected axion mass.

Look at the magnitude of those Q's  (10^6)

They now report testing at much higher frequencies as well: 15 to 120 GHz range. They were previously testing in the 0.81 to 0.86 GHz range, see:  http://forum.nasaspaceflight.com/index.php?topic=29276.msg1263849#msg1263849

Eagleworks run the Frustrum at 1.94 GHz  (twice the value of what ADMX run before, but less than 7 times what they report now in this slide).

They are also running with a lower magnetic field (3 T and 6 T instead of the previously reported >7 T)

They are spacing the dielectric resonators by 1/2 the wavelength in the waveguide.

Ok...if I am following this correctly, then the spec's for the axiom experiment in Italy are now much closer to being in line with spec's for the Eagleworks 'propellentless drive'...apart from the missing (?) electromagnetic field?

That said, in the paper that set off this thread, the Eagleworks team did seem to think they'd be able to manufacture a much more powerful thruster for the next set of tests.  Assuming they get anywhere near the hoped for results with the new device, would this invalidate the axiom angle? 

Online Notsosureofit

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Re: EM Drive Developments
« Reply #1162 on: 09/30/2014 01:43 AM »
Nope, but the axiom angle might be related to any frequency difference between 2 photons.

Hmmm, notice the nonlinear waveform in slide 28 ?

Reminds me that dielectric layers can be used to isolate the electric and magnetic interactions (as in the dielectric/metal/dielectric optical filter).  Maybe in the COMSOL model of the Sawyer resonator ?

Now there's a thought, if the axion is it's own antiparticle, perhaps the decay is so weak in a simple resonator because the 2 photons are out of phase.
« Last Edit: 09/30/2014 02:19 AM by Notsosureofit »

Offline Rodal

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Re: EM Drive Developments
« Reply #1163 on: 09/30/2014 02:17 AM »
Nope, but the axiom angle might be related to any frequency difference between 2 photons.

Hmmm, notice the nonlinear waveform in slide 28 ?

ADMX (Washington Univ.) axion (dark matter) experiment

They have several dielectric resonators strategically located such that they are placed at the valleys of the waveform in the waveguide:

You are right, the nonlinearity (straighter, sharp waveform negative peaks) is inside the dielectric-blocks.

The waveform in the cavity regions between the dielectric-blocks has a harmonic shape, by comparison.

Also observe that the field in their waveguide cavities (between the dielectric blocks) reaches high resonance.

______________________________________________________________

NASA Eagleworks Tapered-Cavity Frustum

It has a single disc dielectric resonator with an inner hole.

By comparison, look at the field inside the Eagleworks frustum ("tapered cavity"):practically nothing is going on in the cavity itself (it is all uniform blue: very low values, practically no gradient) and only the PTFE ("Teflon") dielectric resonator reaches (red)  high values and it has a high gradient.
« Last Edit: 09/30/2014 01:17 PM by Rodal »

Offline aceshigh

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Re: EM Drive Developments
« Reply #1164 on: 09/30/2014 02:27 AM »
The LHC and the discovery of the Higgs Boson also relied on tens of trillions of data points. Before they started looking for new science, they made sure they rediscovered every other standard model particle to verify that their instruments were accurately calibrated. The discovery of the Higgs Boson relied on the legacy of many other scientific instruments, rather than just the Large Hadron Collider's detectors. Even then, it's accepted scientific literature, in large part, because reproduction steps are available to anyone willing to build another large particle accelerator.

The secret to the LHC's success is a long history of collaboration and openness about their scientific results. Secrecy is the enemy of progress.


another secret is the huge amount of money they have. Imagine a single guy trying to discover the Higgs Boson with an apparatus created with his own money. And other labs not interested in replicating the experiments unless you give yourself the machine you built (and they just use other methods to test).

and your signals are not that strong. You see only hints of the Higgs Boson in your machine.

When you look at it this way, it looks even less okay for EM drive proponents to withhold data from the scientific research community. Major research institutions have the resources to find more signal amidst noise than hobbyists could ever hope for. EM drive researchers should be reaching out to the broader scientific community, to give scientists, researchers, and engineers some evidence, and good faith, that there is something worth investigating in that direction.

that´s naive to the extreme.

we all know this is the kind of physics subject that won´t be touched with a ten foot pole, if not by scientists, by the institutions that grant research money.

the reaction of most will be the same seen here in most of the thread. Like by GoatGuy. By doing arithmetic, it clearly violates several physics laws and thus is impossible and in the realm of the crackpots.

and will atribute the noise to experiments faults.

it´s a chicken and egg question (just rethoric here, from a scientific point of view the egg came first), as most people here were SAYING that Woodward and others should do a test device to test on space, like if that was cheap, and THEN people would accept it was more than noise and invest in tests of their own.


and btw, are you talking about Dr Woodward or about Dr White here? Because Dr Woodward doesn´t hide behind anything. He is quite open. So right there your theory fails, because there aren´t really many people WITH MONEY wanting to invest in testing it.

I think it can be noise or not. I will just sit and wait, but I won´t deduce anything from where there is not enough info to make a good deduction.
« Last Edit: 09/30/2014 02:30 AM by aceshigh »

Offline Rodal

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Re: EM Drive Developments
« Reply #1165 on: 09/30/2014 02:34 AM »
NASA Eagleworks could imitate the design of ADMX waveguide with strategically located dielectric resonators to enhance coupling.  ADMX has reached much higher Q's than Eagleworks.

Offline Rodal

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Re: EM Drive Developments
« Reply #1166 on: 09/30/2014 03:03 AM »
.....

Now there's a thought, if the axion is it's own antiparticle, perhaps the decay is so weak in a simple resonator because the 2 photons are out of phase.

Axion, Photons in terms of “Particles” and “Antiparticles”
E.Guendelman,
Ben Gurion U. , Israel,
4th Patras Conference, DESY, 06/ 21/08

http://axion-wimp2008.desy.de/e30/e247/talk-21-guendelman.pdf

The Scalar QED Picture and its consequences
1. gB(y,z) couples to the “density of charge” like an external
electric potential would do it.
2. The axion is a symmetric combination of particle
antiparticle, while the photon is the antisymmetric
combination.
3.If the direction of initial beam of photons or axions is
perpendicular to the magnetic field and to the gradient of
the magnetic field, we obtain in this case beam splitting
(new result).
4. Known results for the cases where the direction of the
beam is orthogonal to the magnetic field but parallel to
the magnetic field gradient can be reproduced easily.
« Last Edit: 09/30/2014 03:05 AM by Rodal »

Offline raketa

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Re: EM Drive Developments
« Reply #1167 on: 09/30/2014 03:19 AM »
I was suggesting first to proof/disproof in space, because lot of people thinking this is good idea, why we didn't try to make it happen.
I am putting my money where  my mouth is ready to pledge initial $1000 for this project.
1/Could we contact professor Dr Woodward if he will be interesting to participate and build his apparatus for space environment.
2/We have to find who will do crowdsourcing for us. Does anybody have experience or could recommend it somebody who has good reputation.
3/Easiest and cheapest in my opinion will be to install apparatus in trunk of Dragon. And test it after departure from ISS. We will have power, probably not communication.
I think it will be possible to get Elon  approval if we  him show potential of this project to accommodate our device on trunk and put hard switch that will be enabled after Dragon depart from ISS.
4/Contact people that send cellphone to space, maybe they could build for us cheap communication device for our experiment.
I forgot probably tons of important think we have to do, I am sure you will help me to make complete list and find easiest way to do it. Could we do it?

Offline cuddihy

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Re: EM Drive Developments
« Reply #1168 on: 09/30/2014 11:21 AM »
Raketa, read back in the thread a ways, this is not a good idea. Current thrust level for both what Eagleworks and Woodward have studied are too low, and more importantly too inconsistent& not sustained, to provide sufficient impulse to see some an unquestioned effect in orbit, especially in high-drag environment like ISS altitude.

Offline Rodal

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Re: EM Drive Developments
« Reply #1169 on: 09/30/2014 12:14 PM »
Experimental data obtained using Dr. White's NASA inverted torsion pendulum

______________________________

"Serrano Field Effect" Boeing/DARPA device:
(@aceshigh quotes P. March (in another forum) stating that these results are in a vacuum (~5x10^-6 Torr) )

THRUST =   20 to 110 uN  impulse response (not a rectangular pulse)
SPECIFIC FORCE = 1 to 20 N/kW  (225 000 to 4.5 million times larger than a photon rocket)


______________________________

Cannae Testing:
(not tested in a vacuum by NASA)

THRUST =   40 uN  ~rectangular pulse (duration 30s to 40s)
SPECIFIC FORCE:  0.0014 N/kW (up to 300 times larger than a photon rocket)


______________________________

Tapered (Frustum) Cavity Testing: 
(not tested in a vacuum by NASA)

THRUST = 50 to 90 uN  ~rectangular pulse (duration 30s to 40s)
SPECIFIC FORCE=  0.003 N/kW to 0.0054 N/kW (700 to 1200 times larger than a photon rocket)

______________________________



NASA Eagleworks reports very small measured thrust forces (average lower than 100 microNewtons) for all these tested devices in Eagleworks inverted pendulum. 

Eagleworks noted in their report that

<<p. 14 The net force is calculated by accounting for the null force present in the system. Null testing is performed by attaching the RF drive system to a 50 ohm load and running the system at full power. The null force testing indicated that there was an average null force of 9.6 micronewtons present in the as tested configuration. The presence of this null force was a result of the DC power current of 5.6 amps running in the power cable to the RF amplifier from the liquid metal contacts. This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system. The null test data is also shown in Fig. 20.>>

So, the average null force is admitted to be 25% of the thrust force reported for the Cannae device. Eagleworks attempts to account for this null force (current causes the power cable to generate a magnetic field that interacts with the pendulum magnetic damper system) linearly as if it could just subtract this interaction:  Eagleworks does not account for nonlinear coupling in the system.
« Last Edit: 09/30/2014 01:03 PM by Rodal »

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1170 on: 09/30/2014 12:48 PM »
I am not really following all the axion talk.

What is the line of reasoning about dielectrics and axions, blah blah, which pertains to propellantless drive?
Sometimes I just flat out don't get it.

Offline Rodal

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Re: EM Drive Developments
« Reply #1171 on: 09/30/2014 01:18 PM »
Nope, but the axiom angle might be related to any frequency difference between 2 photons.
Hmmm, notice the nonlinear waveform in slide 28 ?
Continued from http://forum.nasaspaceflight.com/index.php?topic=29276.msg1264292#msg1264292

Also see this, ( from 2014 "Hidden-sector photon and axion searches using photonic band gap structures" http://iopscience.iop.org/0954-3899/41/3/035005/pdf/g_41_3_035005.pdf  )

they <<propose a novel experimental approach in which microwave photonic lattice structures form part of a ‘light shining through the wall’-type experiment to search for WISPs. We demonstrate the potential to match and exceed the sensitivities of conventional experiments operating in the microwave regime>>

They use photonic band gap (PBG) structures (http://optoelectronics.eecs.berkeley.edu/ey1993josab102.pdf and    http://en.wikipedia.org/wiki/Photonic_crystal  ): <<Using the technique presented in [27, 28] we have verified that Qs of 10^6–10^9 can be achieved using this type of lattice (comparable to those of SC cavities). In addition to potentially higher Qs, the use of PBG structures enables us to reach frequencies higher than those accessible to conventional microwave structures, thereby covering the regime from a few GHz to the infra-red>>

See below the normalized electric field along the central line between the source and detector. The position of the dielectric scatterers is indicated by the grey lines

Notice even higher nonlinearity in the dielectrics than in the ADMX experiment's paper (shown at the bottom of this post).
« Last Edit: 09/30/2014 01:54 PM by Rodal »

Offline Rodal

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Re: EM Drive Developments
« Reply #1172 on: 09/30/2014 02:02 PM »
....

Reminds me that dielectric layers can be used to isolate the electric and magnetic interactions (as in the dielectric/metal/dielectric optical filter).  Maybe in the COMSOL model of the Sawyer resonator ?
...
Here they fabricate a flexible photonic crystal using alumina balls inserted in a Teflon tube

http://link.springer.com/article/10.1007%2Fs00339-010-5906-7
« Last Edit: 09/30/2014 02:21 PM by Rodal »

Offline Rodal

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Re: EM Drive Developments
« Reply #1173 on: 09/30/2014 02:30 PM »
Can anybody provide a link to information from Roger Shawyer showing the dielectric material Shawyer uses, the dielectric shape and dimensions and the dielectric location ?

Here Shawyer wrote <<we now let the waveguide include a dielectric-filled section at the smaller end of the taper and choose the dimensions to ensure a reflection-free transmission of the beam from the vacuum-filled section to the dielectric-filled section.>> and <<An experimental thruster with a tapered circular air-filled section and a cylindrical dielectric section was designed and manufactured.>>    http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf

So, from that paper, we know that the dielectric is cylindrically shaped and it is located at the small-diameter end of the truncated cone (just like the Eagleworks frustum) but no further details.
« Last Edit: 09/30/2014 03:28 PM by Rodal »

Online Notsosureofit

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Re: EM Drive Developments
« Reply #1174 on: 09/30/2014 05:41 PM »
"and choose the dimensions to ensure a reflection-free transmission of the beam from the vacuum-filled section to the dielectric-filled section."

That doesn't make a lot of sense to me.  On the one hand it suggests that the dielectric is a half-wave "optical" thickness, and on the other hand that would increase the absorption at that end of the cavity and reduce the cavity Q.  (or at least the air part of the cavity Q, since you now have a dielectric resonator being fed from the air cavity)

Offline Rodal

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Re: EM Drive Developments
« Reply #1175 on: 09/30/2014 05:46 PM »
"and choose the dimensions to ensure a reflection-free transmission of the beam from the vacuum-filled section to the dielectric-filled section."

That doesn't make a lot of sense to me.  On the one hand it suggests that the dielectric is a half-wave "optical" thickness, and on the other hand that would increase the absorption at that end of the cavity and reduce the cavity Q.  (or at least the air part of the cavity Q, since you now have a dielectric resonator being fed from the air cavity)
I fully agree.  The theoretical writings (justifying why his inventions don't break conservation of momentum) from Shawyer don't make sense to me either.  But he may have -by chance and by pursuing his microwave idea- into something that works for entirely different reasons.

I also notice that Shawyer started using ferrites (for which he claimed (relative) permittivity ~38, although the usual values are ~14) but he is later talking about "dielectrics" and Eagleworks used PTFE Teflon for their similar "tapered cavity"

« Last Edit: 09/30/2014 05:49 PM by Rodal »

Online Notsosureofit

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Re: EM Drive Developments
« Reply #1176 on: 09/30/2014 06:02 PM »
Wasn't there some sort of comment about the Cannae drive cavity just becoming a matching network for the dielectric in the feed line. ?
« Last Edit: 09/30/2014 06:03 PM by Notsosureofit »

Offline Rodal

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Re: EM Drive Developments
« Reply #1177 on: 09/30/2014 06:17 PM »
Wasn't there some sort of comment about the Cannae drive cavity just becoming a matching network for the dielectric in the feed line. ?
p. 10 of the "Anomalous Thrust ..." paper:

<<COMSOL Multiphysics® Analysis of Cannae Cavities

Computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software, hereafter referred to as “COMSOL®”) illustrates the relative weakness of the electric field in the vicinity of the cavity slots and relative strength of the electric field within the beam pipe, especially in the drive antenna coaxial cable and the region around the cable within the PFTE dielectric slug as seen in Fig. 14. Consideration of the dynamic fields in the ¼ wave resonance tube shows that there is always a net Poynting vector meaning that the RF launcher tube assembly with dielectric cylinder common to both the slotted and smooth test articles is potentially a Q-thruster where the pillbox is simply a matching network.>>


Offline Rodal

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Re: EM Drive Developments
« Reply #1178 on: 09/30/2014 06:22 PM »
Wasn't there some sort of comment about the Cannae drive cavity just becoming a matching network for the dielectric in the feed line. ?

<<A. Tapered Cavity RF Evaluation, General
Figure 15 depicts one of the early COMSOL® models representing an early possible construction of a tapered RF unit alongside the actual construction that was finally implemented as informed by COMSOL® analysis. The RF drive antenna is the lower loop antenna seen in the wireframe representation of the assembly. An S11 (reflected power) plot prediction from COMSOL® is evaluated against the actual S11 output as measured by a vector network analyzer (VNA) connected to the lower antenna. Note that, in practice, a second (RF sense) antenna is present in the thruster in anticipation of implementing a phase lock loop (PLL) control approach to maintain resonance conditions over time. With the presence of the second RF sense antenna, COMSOL® can be used to provide an S21 (two-port delivered power) plot prediction that can also be evaluated against the actual S21 plot from a VNA connected to both the drive and sense antenna. Comparing the S11 and S21 predicted plots with actual plots helps ensure that the RF drive system is properly coupling with the desired electromagnetic mode at a particular frequency.
The COMSOL analysis iteration process was used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster. The geometry of the RF resonator disc is a function of the resonator material’s relative permittivity, dissipation factor, and target resonance mode.>>
« Last Edit: 09/30/2014 06:31 PM by Rodal »

Offline Rodal

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Re: EM Drive Developments
« Reply #1179 on: 09/30/2014 06:26 PM »
Wasn't there some sort of comment about the Cannae drive cavity just becoming a matching network for the dielectric in the feed line. ?

The ones above are the earlier COMSOL analysis (Fig 15 in the report) for the future Frustum Tapered Cavity.

Here is the analysis for the future Frustum:
« Last Edit: 09/30/2014 06:32 PM by Rodal »

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