Why do wires attract each other when current flows in the same direction?

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Discussion Overview

The discussion revolves around the phenomenon of attraction between parallel wires carrying current in the same direction, exploring the underlying magnetic fields and their implications. Participants examine concepts related to magnetism, including the nature of magnetic poles, field lines, and the distinctions between different magnetic configurations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that wires carrying current do not have recognized North or South poles, as the magnetic field lines circulate around the wires.
  • Others argue that the terms "north" and "south" are simplifications and that magnetic fields do not have defined starting or ending points, with attraction occurring when field lines are aligned in the same direction.
  • A participant expresses confusion about how compasses indicate a wire has magnetized dipoles, questioning the representation of magnetic fields as dipoles versus monopoles.
  • There is a discussion about the misleading nature of the term "dipole" in the context of wires, with some asserting that the circular nature of magnetic field lines is more relevant than the traditional definitions of magnetic poles.
  • One participant seeks clarification on whether a current-carrying wire can be considered a dipole or a monopole, comparing it to solenoids, which are easier to visualize as magnetic dipoles.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of magnetic fields in relation to current-carrying wires, with no consensus reached on the terminology and conceptual understanding of dipoles versus monopoles.

Contextual Notes

Participants highlight limitations in understanding the nature of magnetic fields, particularly regarding the definitions of magnetic poles and the representation of field lines. There is also an acknowledgment of the complexity of visualizing magnetic fields in different configurations.

Jack98
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Hi all, the question is in regards to magnetic fields in a wire. Please refer to illustration below to understand my question.
(https://www.imageupload.co.uk/image/B9f1)

As you can see in Picture 3 two wires parallel to each other will attract each other if the current is going in the same direction. How does attraction occur? Why don't the wires repel each other since the wire acts like a magnet with the same dipoles parallel to other. For example. t's like 2 magnetic dipoles north and south parallel to each other.

If we apply this same scenario but the wire is a magnet on a horizontal plane it makes sense but as you can see in picture 1 this is not correct. In picture 1 if the wire was a magnet on a horizontal plane why doesn't it show the results of picture 2?

Thank you in advance and sorry if it's a silly question. I'm really struggling figuring it out and I know there are smart people on this forum.
 
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Welcome, @Jack98 to Physics Forums!

Your curiosity for getting the answer to this question is genuine and I appreciate your concern.

We, in here, try to answer such questions and support the various concepts regarding a specific subject.
And you are fortunate enough to know that, we have already attempted to answer to this question.
I am giving you the link of one of the thread of PF(PhysicsForums) discussing the answer to the same question.
Here it is,

https://www.physicsforums.com/threads/why-do-parallel-currents-attract.39472/

I would suggest, to read all the thread replies for understanding this concept in detail.
:thumbup:
 
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Likes   Reactions: davenn and cnh1995
Wires carrying current have no recognised N or S poles, the force lines go around the wires.
 
Yeah, I think the source of the confusion here is that you treat "north" and "south" as actual entities, whereas they are just convenient simplifications of the (usual) bar-type magnet.

There is no start or end to a magnetic field, all field lines are closed loop. So, what really matters when it comes to attraction/repulsion is whether the field lines of the two magnetic fields meet head-on (repulsion) or are in the same direction (attraction).
 
Shubham Jaydeokar said:
Welcome, @Jack98 to Physics Forums!

Your curiosity for getting the answer to this question is genuine and I appreciate your concern.

We, in here, try to answer such questions and support the various concepts regarding a specific subject.
And you are fortunate enough to know that, we have already attempted to answer to this question.
I am giving you the link of one of the thread of PF(PhysicsForums) discussing the answer to the same question.
Here it is,

https://www.physicsforums.com/threads/why-do-parallel-currents-attract.39472/

I would suggest, to read all the thread replies for understanding this concept in detail.
:thumbup:

Thank you very much for the link you provided. I hope I find answers to my question.
 
lychette said:
Wires carrying current have no recognised N or S poles, the force lines go around the wires.
Why do compasses show a wire has magnetised dipoles? I'm really confused. I understand magnetic fields are a concept.
 
rumborak said:
Yeah, I think the source of the confusion here is that you treat "north" and "south" as actual entities, whereas they are just convenient simplifications of the (usual) bar-type magnet.

There is no start or end to a magnetic field, all field lines are closed loop. So, what really matters when it comes to attraction/repulsion is whether the field lines of the two magnetic fields meet head-on (repulsion) or are in the same direction (attraction).

That makes good sense and it's help me further understand magnetism but don't we represent the rotation of the fields as north or south? For example the north field lines are attracted to the south pole in a closed loop. Electric charge fields can be both monopole and dipoles but magnetic fields can only be dipoles does current going through a single wire have dipoles or is it a mono pole? Solenoids is a magnetic dipole and it's easier for me to visualise and understand then a single wire, which I can't wrap my head around.
 
I find the use of the term "dipole" entirely misleading when it comes to magnetism.

As you yourself found out, "North" and "South" don't make much sense when it comes to wires. That's because those terms are kinda shoddy, and only serve as a convenience for when a massive body generates a magnetic field. Where the magnetic fields exit the body people call it "North", where it reenters it's called "South". But of course the magnetic field continues inside the body. So, what's special about those two ends? Nothing really. You could see shave off a centimeter at the ends of a bar magnet, and have new North and South ends.

All that matters are the circular field lines. And the direction of them is defined through their "handedness", either right handed or left handed.
 

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