Amplification of electromagnetic fields by a rotating body

https://www.nature.com/articles/s41467-024-49689-w

by keepamovin • 2 years ago

146 71 2 years ago

cdiamand• 2 years ago

Could this be used as an engine of some kind? The spinny thing giving off EM waves and those waves are caught by something like a solar sail?

floatrock2• 2 years ago

No idea, but "amplification", "electromagnetic fields", "rotating bodies", and "published in Nature" are the keywords that get all the UAP podcasters drooling.

Get ready for an onslaught of "Physics behind flying saucers LEAKED" clickbait coming to a feed near you. Whether any of it is actually applicable doesn't matter, the clicks must flow.

fooker• 2 years ago

"Flying saucers are closer than you think, and all my bitterness about academia"

ricksunny• 2 years ago

I'm picking up a lot of projection in this reply;

• To know what keywords get UAP podcasters drooling, you must have watched your fair share of UAP podcasts.

• Your comment is the only one so far to make the association between the article's keywords & UAP, implying that you are yourself making the same association that someone interested in watching UAP podcasts would be making, in which case..:

• ...what is the difference between you and the would-be viewer of the next UAP podcast you are warning away?

BlueTemplar• 2 years ago

Huh, so Unidentified Flying Objects have been renamed to Unidentified Anomalous Phenomena...

thehappypm• 2 years ago

Perhaps in reverse (which should be equivalent, since Maxwells laws are time reversible).. rather than having waves amplified by stealing energy from the cylinder, waves could amplify the rotation of the cylinder.

sharpshadow• 2 years ago

“The fastest rotation achievable by standard motors is of the order of 10 kHz and a record of 667 kHz is reported for a millimetre-sized magnetically levitated sphere.”

From the spinning metal cylinder you can extract EM energy. It’s like a flywheel. The trick is how do you bring up the spin in the first place. The indication here is I guess that you can amplify the spin with EM waves.

“…depending on its rotation speed Ω compared to the field oscillation frequency ω, it can either absorb or amplify.”

westurner• 2 years ago

ScholarlyArticle: "Amplification of electromagnetic fields by a rotating body" (2024) https://www.nature.com/articles/s41467-024-49689-w

Could this be used as an engine of some kind?

What about helical polarization?

"Chiral Colloidal Molecules And Observation of The Propeller Effect" https://pmc.ncbi.nlm.nih.gov/articles/PMC3856768/

Sugar molecules are asymmetrical / handed, per 3blue1brown and Steve Mould. /? https://www.google.com/search?q=Sugar+molecules+are+asymmetr....

Is there a way to get to get the molecular propeller effect and thereby molecular locomotion, with molecules that contain sugar and a rotating field or a rotating molecule within a field?

Vox_Leone• 2 years ago

At first glance, the concept appears to serve as the basis for a 'portable' magnetic field generator, which could be installed on an interplanetary spacecraft.

Filligree• 2 years ago

Or you could use an ordinary electromagnet.

m4rtink2• 2 years ago

Definitely getting some giant magnetoresistence vibes - you know, that thing that (among other things) makes modern hard drives possible: https://en.m.wikipedia.org/wiki/Giant_magnetoresistance

bloopernova• 2 years ago

(I didn't understand the math in the paper)

Would this mean that a rotating body in space would eventually slow down? In other words, amplifying EM radiation draws energy from angular momentum?

dvh• 2 years ago

There's a similar effect https://en.wikipedia.org/wiki/Yarkovsky_effect

javajosh• 2 years ago

Cool. Also may be useful to read Zel'dovich's second paper on the phenomena. http://jetp.ras.ru/cgi-bin/dn/e_035_06_1085.pdf Interestingly, in his paragraph about previous work, he did not mention Yarkovsky:

"According to a remark by P. L. Kapitza, the effect is analogous to amplification of sound by reflection from a resting-medium boundary that moves with supersonic velocity... In the case of plasma waves, a similar effect was considered recently by Ostrovskil. Mention can also be made of earlier studies dealing with the motion of a conducting liquid in a resonator or the motion of carriers in the interior of an elastic piezoelectric or over its surface."

m463• 2 years ago

reminds me of:

https://en.wikipedia.org/wiki/Crookes_radiometer

ptsneves• 2 years ago

On a wiki rabbit hole from that link to the Apophis asteroid, to rage and rage 2 video game plots.

ko27• 2 years ago

Yes, it probably even works in total isolation from any radiation, because it can interact with quantum vacuum and give off energy to create photons. That's the next thing they are trying to prove.

trdtaylor12• 2 years ago

The experiment provides support to the idea that the Superradiance effect (where waves are amplified when interacting with rotating black holes) may not be pulling energy from the blackhole, but from different dimensions. In theories involving extra dimensions (like those proposed in string theory or braneworld scenarios), rotational effects could alter how energy and momentum are distributed across dimensions, leading to observable phenomena similar to what was demonstrated in the experiment.

If rotation within this higher-dimensional space causes analogous effects to the rotational amplification observed in the experiment, it could imply new ways of energy transfer between dimensions. AKA -- ZPM from Stargate

AnimalMuppet• 2 years ago

What? There is no pulling energy from different dimensions here - it's pulling it from the angular rotational energy.

phkahler• 2 years ago

The plot in figure 4 looks a lot like the torque/frequency plot of an induction motor.

photochemsyn• 2 years ago

That would fit:

"Here, we show that this 60-year-old long-sought effect has been concealed for all this time in the physics of induction generators. Induction motors are constituted of two components: an external stator, composed of circuits generating a rotating magnetic field, and a rotor, also composed of several elementary circuit loops, usually in a squirrel cage configuration. By replacing the internal circuits of the rotor with a solid metal cylinder as in Zel’dovich’s original proposal, and using a gapped toroid within a LC resonator as stator, we isolate the key physical effect and unambiguously observe Zel’dovich amplification, which manifests itself as a negative dissipation induced by the rotor in the LC circuit."

krunck• 2 years ago

I keep thinking about all the sci-fi I've seen where a machine with rotating parts opens up a portal or a wormhole...

simcop2387• 2 years ago

Honestly it reminds me a bit of the macguffin used to amplify a signal to insterstellar distances used in The Three Body Problem book. Which given the rest of the novels makes me a little scared

noitpmeder• 2 years ago

Instantly thought of this as well. Loved that book.

pantulis• 2 years ago

Liberate tute me

m4rtink2• 2 years ago

Just don't travel trough warp withou a Gellar Field, unless you really know what you are doing. ;-)

seanw444• 2 years ago

Reminds me of Kerr-Newman black holes.

jjk166• 2 years ago

https://en.wikipedia.org/wiki/Halo_Drive

Oarch• 2 years ago

As someone uneducated in the subject I'm curious what stopped this being discovered earlier? Is the setup particularly challenging?

munchler• 2 years ago

The challenge is in making a physical object rotate fast enough to produce the effect. The article says "the fastest rotation achievable by standard motors is of the order of 10 kHz", which is apparently too slow. The frequency of visible light, for comparison, is about 400–700 terahertz (THz).

trdtaylor12• 2 years ago

Yes; in the same way you can influence gravity by a spinning mass, albeit we do not possess (by orders of magnitude) material or energy required to spin a mass fast enough to detect an effect. Spinning supermassive blackholes show a gravitation/time frame-dragging effect dependent on speed of spin. Showing it occurs with EM is amazing.

colanderman• 2 years ago

Apparently this effect applies to sound waves as well: https://arxiv.org/pdf/2005.03760

ricardobeat• 2 years ago

Does this mean impossibly small subwoofers? Would the rotating part have to precisely match the audio frequency to be amplified?

foobar1962• 2 years ago

The mechanical driver part of the subwoofer might be able to be made smaller, but the surface that moves the air still needs to be large - there is a relationship to the wavelength of the sound involved that I no longer remember. This is why tweeters are small.

mikewarot• 2 years ago

So, if you use eddy currents to delay the phase of an exciting field long enough that the object those eddy currents are inside of can spin more than 90 degrees, the response eddy current fields now AID instead of opposing the original field?

This sounds quite a bit like what Steorm[1] was doing years ago. If ultraconductors[2] worked, you could actually build a mechanical device that had losses low enough to actually gain energy once a critical speed were obtained.

[1] https://en.wikipedia.org/wiki/Steorn

[2] https://patents.google.com/patent/US5777292A/en

(Claim 7 is for material with a conductivity of 10^11 S/cm, which is 150,000 times better than copper)

mmastrac• 2 years ago

This sounds quite a bit like what Steorm[sic] was doing years ago

Steorn was a scam, and they never actually showed anything off. The only thing they did was rob some investors.

Terr_2• 2 years ago

If ultraconductors[2] worked, you could

Not familiar with that idea, but this construction sounds a bit like: "If only you had an (infinitely) rigid rod, you could push one end to communicate faster than lightspeed."

Or in balder terms: "If only we had a subtly impossible component, we could make a blatantly impossible machine."

MadnessASAP• 2 years ago

I am somewhat curious where the math on a perfect rigid rod breaks down (that is, where does the 0 end up under the line)

hi_hi• 2 years ago

So a perpetual motion device!?

jovas• 2 years ago

Could it be true for gravitational waves?

winwang• 2 years ago

I'm not sure if the maths are related, but there is a different (though similar) idea in gravitational slingshots. It's not the same because it simply uses "normal" linear momentum. But I also only read the abstract, lol.

myself248• 2 years ago

Sounds like a crappy Alexanderson alternator.

sfink2• 2 years ago

Dumb question: why is it hard to make something spin really fast?

Simple example: put your frictionless spherical cow on a spinny plate. Make it a very small cow; it's only there to have a point of rotation. Why frictionless? You don't want its butt to catch fire. Why spherical? It'll need to maximize volume dedicated to arm muscles; see below.

Have the cow hold two ropes, each leading to a full-sized cow 10m away. Apply force to those cows (blow on them, or magnetize them and do a solenoid thing, or just make them very gassy cows and orient their spherical butts in opposite directions). Get them spinning at 1Hz. (This is very fast; remember the diameter is 20m.) Now have the middle cow pull the ropes, shortening them to 10cm. It's now spinning at 1Khz. 10mm gives 1Mhz. Conservation of angular momentum, baby.

Do this in a vacuum in microgravity, and you don't need the center cow.

Sure, if you're doing this at a bovine scale, the tension is ridiculously large. What makes it infeasible at a small scale?

mjewkes• 2 years ago

Centrifugal forces on the spinning object will tear it apart once it goes “really fast”

Thorondor• 2 years ago

The main issue is that when objects spin really, really fast, they tend to explode due to centrifugal force.

The tensile stress on a spinning round, homogeneous object is p * r^2 * w^2, where p is density, r is radius, and w is angular velocity. Using your numbers for a steel cylinder with density 8 g/cm^3 gives a tensile stress of (8 g/cm^3) * (5 mm)^2 * (2pi*1 MHz)^2 = about 8 TPa which vastly exceeds the tensile strength of steel or any other known material. Using cows connected by ropes would be even worse because the enormous centrifugal force would be borne by only a small rope.

dexwiz• 2 years ago

There are some great examples on youtube of people demonstrating this with skateboard wheels and compressed air.

sfink2• 2 years ago

That makes sense. With (strong) steel maxxing out at around 1Gpa, that's 4 orders of magnitude less. The rotation frequency gets squared, so... 10Khz? Huh: "The fastest rotation achievable by standard motors is of the order of 10 kHz". (How does a "standard motor" achieve 10 KHz without ripping apart, then? I don't think many standard motors are 5mm or smaller.)

Thinking about this makes me imagine a potter's wheel for shaping a ductile metal. It spins really fast, but you can only reshape in the outwards direction, and the resistance goes up dramatically towards the center. Oh, and if anything flakes off, you're dead. But before you die, you could probably make some pretty artwork.

keepamovin3• 2 years ago

It would be great if the electric effects of spinning fast could result in a reduction in inertial mass to counteract the tendency to disintegrate

keepamovin3• 2 years ago

I suppose another idea is what if you used a fluid?

- A non-Newtonian fluid

- A ferrofluid

- A non-Newtonian ferrofluid

- Or, a liquid metal, like:

  - gallium, or 

  - mercury

as the spin mass

Amplification of electromagnetic fields by a rotating body

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