A circular current-carrying wire floats in space....

AI Thread Summary
The discussion revolves around the behavior of a circular current-carrying wire in space, particularly focusing on the forces acting on it due to its own magnetic field. Participants explore whether the wire twists or stabilizes itself under the influence of Lorentz forces. Initial assumptions about the direction of these forces shift from inward to outward, suggesting a self-stabilizing mechanism. There is also debate about the presence of a magnetic field within the wire itself, with some arguing that it may cancel out entirely. The conversation ultimately draws parallels to the forces experienced by two parallel current-carrying wires, extending the concept to a circular configuration.
rumborak
Messages
706
Reaction score
154
Maybe there's a tiny battery somewhere, just to make it realistic. The wire is also very thin, and thus needs little to no force to be bent.

What happens to the wire? Does it twist on itself because each piece of the wire experiences a Lorentz force due to the magnetic field of the wire on the other side of the circuit?

EDIT: Just did some sketching, it looks like the forces point inward indeed. So, I may have answered my own question :)

EDIT 2: Correction, the forces point outward. That could mean it is self-stabilizing, since any part of the wire going outward (experiencing less magnetic field as a result) would require another one to go inward (experiencing more field).
 
Last edited:
Physics news on Phys.org
rumborak said:
Correction, the forces point outward. That could mean it is self-stabilizing, since any part of the wire going outward (experiencing less magnetic field as a result) would require another one to go inward (experiencing more field).
I am not sure if I understand the scenario clearly. Is the force acting on the wire because of its own field?
The field of a circular current carrying loop looks like this.
images (7).png

It appears from the diagram that there is no field at the site of the wire.

In all the situations that I have seen before, where there is a force on a current carrying conductor, it is because of the magnetic field from some other source (e.g in dc motors, short circuit fault in transformer, PMMC, MI or EDM type measuring instruments etc.)
 
Yeah, I'm considering only the forces the wire exerts on itself.

Hmm, the pic you posted would suggest there is no magnetic field inside any of the wires. That's just a simplification though, right? There should be a minor magnetic field due to the magnetic field originating on the other side. Or is this one of those cases where everything exactly cancels out so that there really is no magnetic field inside the wire?

The way I'm imagining this is an extension of the classic "two parallel current-carrying wires are exerting forces on each other", only in a circular sense.
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
Back
Top