Can You Shape a Magnetic Field?

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Discussion Overview

The discussion revolves around the possibility of shaping or extending the range of magnetic fields produced by neodymium magnets. Participants explore various methods and materials that might influence the behavior of magnetic fields, including the use of soft iron, superconductors, and other conductive materials. The conversation touches on theoretical aspects of magnetism as well as practical applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that while neodymium magnets are strong, their effective range is limited, prompting a question about how to extend this range.
  • Another participant asserts that there is no practical way to create a 'focussed' magnetic field, although soft iron can be used to conduct magnetism.
  • A different viewpoint mentions the use of aluminum or copper sheets to 'stretch' the magnetic field, although this is met with skepticism regarding its effectiveness.
  • It is noted that a magnetic field requires a return path, which limits options for 'stretching' the field and necessitates additional components.
  • One participant claims that superconductors can effectively extend the range of magnetic fields, particularly in the context of permanent magnets.
  • A question is raised about whether connecting two permanent magnets with a soft iron rod would extend the magnetic field as if it were a single magnet, with a follow-up inquiry about the impact of the rod's diameter.
  • A theoretical approach is introduced, suggesting that representing magnets as magnetic monopoles could allow for separation without altering their strengths.
  • Another participant humorously suggests that using a stick to extend the reach of a magnet is a practical solution, while also mentioning the concept of using an iron core in a solenoid to collect field lines.

Areas of Agreement / Disagreement

Participants express a range of views on the methods to influence magnetic fields, with no consensus reached on the effectiveness of proposed solutions. Some ideas are challenged or refined, but the discussion remains unresolved regarding the best approach to extend the range of magnetic fields.

Contextual Notes

Participants acknowledge limitations in their understanding of magnetic fields, including the need for a return path and the conditions under which certain materials may or may not be effective. The discussion also highlights the complexity of magnetic interactions and the theoretical nature of some proposed models.

TrustyDelux
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Hi all,

I have been playing around with some neodymium magnets recently and have found that although they are indeed very strong the 'range' of the magnetic field is not very large.

So I was wondering if there is a way to shape the magnetic field so that the magnets would attract/repel each other from a greater distace.

Hope I've made myself clear! :)

Thanks.
 
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Not in any useful sense.

You can use soft iron to 'conduct' the magnetism much like a wire conducts electricity, but there's no way to get a 'focussed' magnetic beam such as I imagine you are thinking of.
 
Not really trying a 'beam' more like a 'stretched' field. I read somewhere that you can use sheets of aluminium or copper to do this.
 
TrustyDelux said:
Not really trying a 'beam' more like a 'stretched' field. I read somewhere that you can use sheets of aluminium or copper to do this.

Assuming that you understand that a magnetic field is not emissive(in the sense of a monopole) a magnetic field must have a return path to exist(as we currently understand; could change)

Because of this, options to "stretch" the field is limited, and requires additional components.
Even with additional components, the "stretch" is severely limited.
 
Aluminum or copper will only work for alternating magnetic field.

If you have a permanent magnet, the only thing that will achieve this sort of effect is a superconductor. A superconductor does not allow magnetic fields to pass through it (well, Type I doesn't, with Type II it's a little more complicated, but anyways...). So if you have a superconductor tube, and you put a magnet at one end of it, near the other end, it will be as if the magnet is right there.
 
Does connecting two permanent magnets with a soft iron rod extend the field as if it were a single magnet as long as the overall length?
Would the rod being a different diameter make a difference? (assuming identical size magnets)
 
If you represent the magnet as a pair of magnetic monopoles (yes, they aren't real, but it works as a mathematical trick) then yes, something like that can be done to separate the monopoles further without altering their strengths.
 
So is the best way to achieve a larger 'range' to shell out and buy bigger magnets? Or does this only increase the attraction/repulsion force?
 
Last edited:
The range is infinite and magnetic fields are divergence free.

If you want to pick up an iron ball from farther away, tape your magnet to a stick and then use that as an extension.

If you want to "collect" field lines inside a solenoid for example, use an iron core.
 

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