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[Reelya]

Idk about EmDrive, but if anyone thinks emDrive is totally the bomb and cold fusion is complete bunk, you really need to read the relevent literature:
https://www.newscientist.com/article/mg23130910-300-cold-fusion-sciences-most-controversial-technology-is-back/
25 years of media/scientific establishment pressure hasn't killed cold fusion, and the US government is convinced enough that they continue to pour money and research effort in. Then you have plenty of respected physicists around the world who have done experiments that seem to back it up:
http://phys.org/news/2008-05-physicist-real-cold-fusion.html
That's not to mention that the US Navy's Office of Naval Research did 10 years of experiments on it and claim to have positive results.

An interesting new take is that it's not fusion at all, so no new physics is needed, but what happens is that via some known but obscure physics (Ponderomotive forces), cause neutron to break away from light atoms such as deuterium and transferred into the metal lattice. This might explain why there is evidence of transmutation / tritium etc but not of gamma rays and other expected fusion products ... It's a form of nuclear process, but it is neither fusion nor fission.
https://animpossibleinvention.com/2015/10/15/swedish-scientists-claim-lenr-explanation-break-through/
The sources are in Swedish so I can't really verify the linked sources.

So, if all those different groups around the world are doing experiments on low-energy nuclear reactions claiming positive results and it's all just bunk, then I wouldn't say the evidence for emDrive is good either.

[MetalSlimeHunt]

They're probably both complete bunk. Obviously people will (and should) grasp at any straw that would allow us to violate all known standards and acquire ULTIMATE POWER over the universe, but actually holding your breath for any such thing is a grand waste of time.

[Starver]

What went wrong with what?

Spoiler (click to show/hide)

[inteuniso]

They're probably both complete bunk. Obviously people will (and should) grasp at any straw that would allow us to violate all known standards and acquire ULTIMATE POWER over the universe, but actually holding your breath for any such thing is a grand waste of time.

I don't see anything wrong with it. It's just like having a wind chime with the ends closed. And you're using an energy transmitter instead of a gong. Still pretty basic mechanics though.

As for electromagnetic-wave attractions, it's not surprising when you consider that electromagnetism should impart some degree of said magnetism on whatever it passes through. I'm glad someone else did the math on it. I imagine that the energy produced from neutron transfer will be a happy byproduct in a hot fusion reaction, or something used for low-power space applications. Comm buoys or somesuch.

On the fusion note, I wonder when we'll finally notice that functionalized graphene is still carbon and use it to make some steel for fusion reactors. Should definitely be able to withstand the temperatures.

[wierd]

My take on the EM-Drive?

Does not violate any rules, and there IS an exhaust, just not a kind that interacts strongly with the enclosure.


Possible case 1:
Ambient neutrinos given slight push in favored direction because neutrinos have a small magnetic moment, and are massed. Interact only with the magnetic properties of the cavity induced by the high Q oscillation, and not with the cavity wall, and thus pass right through after the interaction.

Possible case 2:
Device is acting like a weaksauce magnetic horn, and is redirecting muons produced from cosmic particle interactions in the upper atmosphere to be given a preferred vector, some of which decay into neutrinos and pass through the back of the device uninhibited. Momentum transferred to the muons is conserved during decay into neutrinos, and is not reabsorbed by the back of the chamber, (because neutrinos interact with atomic nuclei only very weakly), giving a slight push to the chamber.


Suggestions:

Place device in close proximity to a strong source of nuclear decay products, (previously mentioned pions and neutrinos) and see if the quality of thrust goes up in relation to flux densities of these ambient particles.

[Putnam]

Doesn't a magnetic moment require interaction with the electromagnetic force, which neutrinos do not have (seriously, the margins of error on them having it are hilariously small)?

(because neutrinos interact with atomic nuclei only very weakly)

Nono, just weakly. Weak interaction. W and Z bosons and all that.

[wierd]

If they are Dirac neutrinos, they have a magnetic moment proportional to their mass.

http://nucla.physics.ucla.edu/sites/default/files/NeutrinoMagneticMoment_2012Nov8.pdf

[Max™]

You know for a long time we weren't sure they had a mass, much less if they are Dirac rather than Majorana particles, so if it was as simple a thing to interact with them and produce measurable thrust with a microwave cavity as the EM-drive would seem to imply in your scenario, a lot of experimental physicists need to resign in shame.

[wierd]

The thrust levels produced by the EM-Drive are VERY VERY small. That this is hard to determine as a signal "at all" (many assert that the signal is just noise, and that upon closer inspection, it will vanish statistically) is kind what makes me suspect such a very small interaction potential.

The big test is to put a strong beta emitter near the cavity to see if the thrust increases. (a product of beta decay is neutrino emission. A fast decaying beta emitter, like tritium gas, would be ideal.)

If the mostly pure neutrino variable turns out null, putting it in proximity to a strong source of pions (like a fission reactor) would test possible scenario 2 adequately.

[origamiscienceguy]

They tested it in a vaccuum and faced it in several directions. Each time, the thrist came out the nozzle.

[wierd]

That is the preferred vector.

The question is "whence thrust?"

There is seemingly nothing being expelled from the device, so where is the momentum coming from? With WHAT is the chamber interacting?


I offered 2 possible candidates, and how to test them. 

In the case of the redirected neutrinos, increasing ambient neutrino flux (by addition of a small capsule of compressed tritium inside the chamber, which is not electrically involved in the supposed action taking place other than just being a source of neutrinos, passively) would increase the number of neutrinos being interacted with, even if "rate" of interaction was unchanged, resulting in an increase in thrust.

In the case of high energy pions getting through the thin cavity wall, interacting with the magnetic properties of the oscillation, and decaying before they can collide with the back of the cavity-- increasing the local supply of pions (which are normally very short lived-- the ones we get as background come from very high energy collisions in the upper atmosphere, and only live a few seconds, due to their nearly relativistic velocities) would increase thrust values. You can get a very prominent increase in these particle concentrations by putting the test article near to a nuclear reactor. (they get emitted in all directions from the reactor when it is turned on, and operating.)

[Max™]

Ok but, the planet has a magnetic field which rotates within a constant flux of solar neutrinos, if there were a magnetic moment to the neutrino which could be measured on the scale of an EM drive chamber, I'm pretty sure there would be a noticeable effect on the structure and behavior of the terrestrial, and probably jovian fields as well.

Every single neutrino that passes through the planet makes at least two trips through the densest parts of these fields, so it would need to be small enough an effect that it wouldn't show up as any sort of wiggle room in any observations and theoretical explanations of said fields, yet a couple feet of weak EM fields are sufficient to deflect them enough to produce thrust?

[wierd]

or, any effect cancels out due to a symmetrical field.

The field inside the EM-Drive is (claimed to be) asymetrical, due to its pointy shape.

A better question, is if the magnetic horn accelerators used to accelerate muons to create neutrino beams for the NOvA experiment creates "anomalous" thrust.

https://www-nova.fnal.gov/how-nova-works.html

[MetalSlimeHunt]

In fairness, if neutrinos do cause magnetic thrust, we've just been observing that since the first time we ever observed the planetary fields and might not be able to discern the difference. Or the symmetry argument. Or the micronewton thrust isn't enough to cause any meaningful deformation, even on these scales.

[Max™]

A magnetosphere is not as symmetrical as you might think, and there would be some notice of an anomalous deflection of neutrinos here on Earth, most likely with an identifiable relation to the rotation of the planet, or some effect on the structure of the various fields we've been directly observing over the decades if there was a significant magnetic moment to the neutrino.

http://www.mps.mpg.de/planetary-science/planetary-plasma-environment

There isn't room for a theoretical model to fit like that and still produce thrust with such a small input, if the effect only arises under specific and extremely constrained conditions and demands whole new physics to explain, the most likely explanation is that your experiment was poorly designed and/or your observations were flawed, not that we have tapped into pathway towards a cheap neutrino rocket.