Author Topic: EMdrive Developments working in visible and infrared light regime.  (Read 82213 times)

Offline Hakasays

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Moderators note;
New Physics is about experiments being conducted applicable to spaceflight. Theories attempting to resolve the experimental results with known rules of physics are on topic.

This thread was begun by cvbn, it deteriorated into off topic discussions unsuited for this site. At his request I will attempt to restore the relevant posts, please be patient, my moderation skills leave a lot to be desired.
 
cvbn started with a wall of tweets (which just hurts my brain) and a few relevant comments which I have included here. My apologies to him for heavy-handed moderation which results in hakasys being the first poster for this cleaned up thread. PM to me directly all requests for changes to this thread.

cbn original post (minus the head splitting tweets);

"Taylor's paper described an EMdrive working in an optical regime: https://www.jbis.org.uk/paper/2017.70.238 .
 Since then there have been so far at least two attempts to build and test that kind of EMdrive.
DARPA paid to McCulloch and his teams in Spain and Germany $1.3M to test and develop his theory:
https://www.plymouth.ac.uk/news/scientists-receive-13-million-to-study-new-propulsion-idea-for-spacecraft
The team in Germany lead by prof. Tajmar is performing an experiment based on the aforementioned Taylor's optical EMdrive paper (although they found that they were not able with the current funding to build all the supermirrors as described in the paper, so they made a much simpler version). Tajmar reports a thrust that he cannot explain with mundane effects, but he is abstaining from submitting a paper, because he is still looking for a mundane explanation of the thrust (he has not been able to find one so far, though)"


Hakasys post which became the new starting point

Also relevant to experimenters:

I've posted plans for a 3d-printable microgram balance that might prove invaluable to anyone attempting to measure the tiny thrusts allegedly created by these devices:

https://www.thingiverse.com/thing:4261409


Anyone with questions/concerns/requests feel free to DM or contact me on Twitter and I will assist as best as I am able. ;)
« Last Edit: 06/10/2020 10:36 pm by D_Dom »

Offline meberbs

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...

A hollow cavity that is highly internally reflective would be considered a resonant cavity centered within the visual spectrum ~400-800nm.
The Q factor of said cavity would be governed primarily by the reflectivity of tha surface.
No. Resonance is, by definition, a frequency dependent peak, not a broadband ability to reflect things. It is certainly possible to make optical frequency resonators, but it is not done by simply making an arbitrary sized metallic cavity.

In the case of the above experiment, the signal is 400-800nm (depending on the light source used).
Q factor (reflectivity) of the cavity determines the amplitude increase within the chamber.
The sources used are broadband not single frequency. (And tweets also mention infrared, not just the visible range you list. This oversight just further demonstrates that a bunch of tweets is an unhelpful format for describing the experiment details.)
...
« Last Edit: 06/10/2020 10:01 pm by D_Dom »

Offline Hakasays

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We'll just have to agree to disagree on terminology.
I will use whatever definition you find most suitable as I'd rather not pollute the thread any further. :P
This isn't about terminology. The definitions of these concepts are well defined.


I think we can agree that the focus of the thread is more on practical experimentation not whether a QI cavity fits the  definition of an optical resonant cavity.

With your knowledge on the subject, what do you think is the most proper definition for a QI cavity that operates in the optical spectrum?

Offline meberbs

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I think we can agree that the focus of the thread is more on practical experimentation not whether a QI cavity fits the  definition of an optical resonant cavity.

With your knowledge on the subject, what do you think is the most proper definition for a QI cavity that operates in the optical spectrum?
QI is a theory. There is no single object that can be referred to as a "QI cavity." QI supposedly makes predictions about a lot of things, including resonant cavities and things that don't involve resonance. For most of these predictions I have yet to see a decent derivation backing them.

...
« Last Edit: 06/10/2020 10:02 pm by D_Dom »

Offline cvbn

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For most of these predictions I have yet to see a decent derivation backing them.

You have about 30 papers to choose from:
http://quantizedinertia.com/researches/

The main topic of this thread is optical/IR Emdrive (or whatever other name you'd like to choose for this device), so even if (in your opinion) QI is not responsible for these effects, but they are observed, then it is still valid to consider why they are observed. They may be false positives, but at the moment the experimenter was unable to find their cause (other than QI).

« Last Edit: 06/10/2020 10:03 pm by D_Dom »

Offline Hakasays

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I plan on running some QI experiments in the very near future. It will be simpler for me to run these tests as I already have a suitable thrust balance (torsional pendulum) with micro-newton resolution. I am tying up some loose ends with the mach effect now, but when those tests are finished, I hope to have something substantial to show in a week or two.

The cavity is the only issue really. I'm looking at using mirrored blown glass as a cavity for the first tests. Or if someone has a cavity they can send me to test, that would also be an option.  The setup will be very straight-forward since there are 4 liquid metal contacts available.

I do not have a vacuum chamber (yet), but I do have experience with running thrust balance experiments in air with components that heat up rapidly. The easiest solution is to cover the test device with insulation and limit the test duration so that the device does not overheat.  Then wait however long for the device to cool down so the test can be repeated.



Looking forward to it! ;D

As long as you're exploring multiple routes, you may want to consider 'mirror film' as a means to create a crude QI tapered cavity.  Reflectivity is >95% from the calibrated measurements I had done earlier this year.   It's more-or-less comparable with a consumer glass mirror:

https://www.amazon.com/dp/B07C8FQN6T


And one additional method to consider that neither of us have tried yet is chemical deposition via silver nitrate reduction:




You can mitigate some (or most) of the thermal effects by running the device in multiple orientations
(facing up, down, and sideways).

If your scale can pickup rapid changes, you should also see the thermal effects tend to operate on a much longer time domain.  In other words, Lorentian and QI effects appear almost immediately, while thermal effects tend to be delayed by 1-10sec depending on output power.
 ;)


moderators note; Monomorphic, I apologize for clobbering your post, I can't figure how to restore it to this thread. I expanded this quote from your original post and added the pictures below.
« Last Edit: 06/10/2020 10:41 pm by D_Dom »

Offline Hakasays

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It - at least as described here - has been falsified through experiments and observations, though.  Experiments and observations he is citing, and you are ignoring.

You donít get to just ignore whatever aspects of established physical theory (and the experiments underlying it) you dislike.  And thatís what youíre doing, as are those referenced here who just start with the statement that GR has been falsified.

I didn't see much in the way of data or citations, just some general statements wrapped in a blanket of hostility.  I'm focused more on specific or experimental data.

The data in the papers that I've read looked promising (mostly relating to recent experiments on EMDrive) and were consistent with some views that I already held relating to special relativity:

https://www.researchgate.net/publication/316650291_Testing_quantised_inertia_on_emdrives_with_dielectrics

Or at least promising enough to convince me to build it :P

Offline Monomorphic

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If your scale can pickup rapid changes, you should also see the thermal effects tend to operate on a much longer time domain.  In other words, Lorentian and QI effects appear almost immediately, while thermal effects tend to be delayed by 1-10sec depending on output power.

This is an example of the data from a calibration signal using a voice coil mounted off the balance and a small magnet mounted on the balance. One can see that the signal is nearly instantly detected. This is the type of signal expected if it is real thrust.

Blue is the displacement of the balance arm and orange is the calibration coil power on/off.
« Last Edit: 06/08/2020 11:43 pm by Monomorphic »

Offline D_Dom

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Thanks Monomorphic for your contributions. Experimental results are the best aspect of these "New Physics" topics. I appreciate your diligence and dedication to the scientific method.
« Last Edit: 06/13/2020 05:34 pm by D_Dom »
Space is not merely a matter of life or death, it is considerably more important than that!

Offline Hakasays

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If your scale can pickup rapid changes, you should also see the thermal effects tend to operate on a much longer time domain.  In other words, Lorentian and QI effects appear almost immediately, while thermal effects tend to be delayed by 1-10sec depending on output power.

This is an example of the data from a calibration signal using a voice coil mounted off the balance and a small magnet mounted on the balance. One can see that the signal is nearly instantly detected. This is the type of signal expected if it is real thrust.

Blue is the displacement of the balance arm and orange is the calibration coil power on/off.

Mono, what do you use for a voice coil?  I've been using an interferometer-based setup but your method would have a faster response and be far easier to graph.
I have a small geophone laying around that I think might work? ???

Offline meberbs

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For most of these predictions I have yet to see a decent derivation backing them.

You have about 30 papers to choose from:
http://quantizedinertia.com/researches/
None of which that I have seen actually provide a coherent derivation of predicted effects, generally there are significant flaws in what is provided.

The main topic of this thread is optical/IR Emdrive (or whatever other name you'd like to choose for this device), so even if (in your opinion) QI is not responsible for these effects, but they are observed, then it is still valid to consider why they are observed. They may be false positives, but at the moment the experimenter was unable to find their cause (other than QI).
After the cleanup removing irrelevant things, it is even more clear to see that this thread lacks a clear description of any experiment demonstrating possibly real effects. The emDrive threads on here have long since demonstrated that there are many ways to generate false positives, and some are hard to notice or account for.

Offline meberbs

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It - at least as described here - has been falsified through experiments and observations, though.  Experiments and observations he is citing, and you are ignoring.

You donít get to just ignore whatever aspects of established physical theory (and the experiments underlying it) you dislike.  And thatís what youíre doing, as are those referenced here who just start with the statement that GR has been falsified.

I didn't see much in the way of data or citations, just some general statements wrapped in a blanket of hostility.  I'm focused more on specific or experimental data.

There was, though it got lost in the thread cleanup. For details, you an go read the previous thread on QI.
https://forum.nasaspaceflight.com/index.php?topic=48497.0
If you want an experimental demonstration that QI is wrong, the Pioneer anomaly is a good example. Accounting for originally un-modelled effects of assymetric thermal radiation removed the anomaly.

The data in the papers that I've read looked promising (mostly relating to recent experiments on EMDrive) and were consistent with some views that I already held relating to special relativity:

https://www.researchgate.net/publication/316650291_Testing_quantised_inertia_on_emdrives_with_dielectrics

Or at least promising enough to convince me to build it :P
If you carefully read through the paper, it isn't promising at all, there are basic mistakes, such as equation 7 which makes no sense, the photons do not have rest mass, so this should be handled more carefully, but the biggest problem is that the photons are travelling in different directions, their net momentum at any time is going to be 0, or something close to that in a stationary resonating cavity, not proportional to the energy (like it would be in a unidirectional laser beam.) No need to get into things like the the various baseless assumptions he makes.

If you want to run an experiment that is fine, but you should set your expectations appropriately, and no experiment can rescue a fundamentally flawed theory. Math errors, contradictory usage of terms, and contradiction with other experiments will remain.

Offline Monomorphic

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Mono, what do you use for a voice coil?  I've been using an interferometer-based setup but your method would have a faster response and be far easier to graph.

The voice coil is not what detects the movement.  Detection of movement is accomplished by two laser displacement sensors. One for horizontal (the direction one would expect thrust) and one for vertical displacement.  You can pick these up on ebay for $400 - $500 each.  Then all you need is a suitable Analogue-Digital Converter (ADC).

The voice coil is used to exert a known force on the torsional pendulum to make sure it is working properly.

The direction I am heading in now for the experiment is a more traditional optical cavity.  I have been running some simulations on bouncing a laser beam inside mirror cavities of various geometries with interesting results (video below).  I have confirmed some of these results with a crude mirror system and a 250mW laser. 



« Last Edit: 06/16/2020 01:19 am by Monomorphic »

Offline Hakasays

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Thanks, Monomorphic, I did not know displacement sensors of high quality were so cheap.
That would have saved me a couple months of tinkering with handmade interferometer-based setups. (no regrets, I learned a lot in the process ;D)

Offline Monomorphic

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Thanks, Monomorphic, I did not know displacement sensors of high quality were so cheap.
That would have saved me a couple months of tinkering with handmade interferometer-based setups. (no regrets, I learned a lot in the process ;D)

The laser displacement sensors are $3000+ new.  I lucked out and got two used that were like new a few years ago.

Offline Bob Woods

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Mono, what do you use for a voice coil?  I've been using an interferometer-based setup but your method would have a faster response and be far easier to graph.

The voice coil is not what detects the movement.  Detection of movement is accomplished by two laser displacement sensors. One for horizontal (the direction one would expect thrust) and one for vertical displacement.  You can pick these up on ebay for $400 - $500 each.  Then all you need is a suitable Analogue-Digital Converter (ADC).

The voice coil is used to exert a known force on the torsional pendulum to make sure it is working properly.

The direction I am heading in now for the experiment is a more traditional optical cavity.  I have been running some simulations on bouncing a laser beam inside mirror cavities of various geometries with interesting results (video below).  I have confirmed some of these results with a crude mirror system and a 250mW laser. 

Care to discuss the trial at 5 min where you appear to have created a reflection trap? Have you let that sim run at that configuration to determine if it eventually diverges?

I note it's a little frustum-ish.... ;D
« Last Edit: 06/16/2020 06:33 am by Bob Woods »

Offline Monomorphic

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Care to discuss the trial at 5 min where you appear to have created a reflection trap? Have you let that sim run at that configuration to determine if it eventually diverges?

Those are interesting. I checked and it escapes very soon after the video stopped. This particular geometry is very efficient at recycling photons.  There was another one I found that was similar I have also posted below.

So far, the longest lived geometry I have seen is over 100 bounces.  That reflection appears to be random, though.
« Last Edit: 06/16/2020 02:07 pm by Monomorphic »

Offline Monomorphic

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Images of the crude proof-of-concept built out of regular mirrors and a 250mw 450nm laser I had from another project.  It is crucial that each freedom of degree be adjustable by small increments.

The 7-watt laser arrives Friday. That should give me enough time to 3D print the rest of the parts. I also have to make the first surface mirrors. This involves cutting regular mirrors to size and then dissolving the protective coating on the back of the mirror to reveal the aluminum.
« Last Edit: 06/17/2020 07:15 pm by Monomorphic »

Offline Bob Woods

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So far, the longest lived geometry I have seen is over 100 bounces.  That reflection appears to be random, though.


Angle of incidence = angle of reflection. Not random.

Offline meberbs

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So far, the longest lived geometry I have seen is over 100 bounces.  That reflection appears to be random, though.


Angle of incidence = angle of reflection. Not random.
That last picture in that post seems to show aiming right into the corner, which the sim handles by taking a reflection from a surface halfway in between as if it was a rounded corner. This isn't truly random, but could seem that way due to high sensitivity to initial conditions.

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