# Need help with making sphere electromagnet

1. Apr 13, 2013

### vinknee

I am trying to make an electromagnet sphere shape about 6 inches OD. Is this possible?

2. Apr 13, 2013

### jambaugh

You can make an electromagnet in the shape of Daffy Duck, take a Daffy Duck shaped piece of iron and wrap wire around it.

3. Apr 13, 2013

### DrZoidberg

Depends. What shape do you want the magnetic field to have?

4. Apr 13, 2013

### Staff: Mentor

A spherical symmetry for the field is impossible, but "spherical object with some magnetic field" is no problem.

5. Apr 13, 2013

### technician

[deleted my response

Last edited: Apr 13, 2013
6. Apr 13, 2013

### milesyoung

You'd need to produce a magnetic monopole to get a field with spherical symmetry.

If you succeed, I'd like to be the first one to invest!

7. Apr 13, 2013

### technician

deleted my response

Last edited: Apr 13, 2013
8. Apr 13, 2013

### milesyoung

The vector field should depend only on the distance to whatever origin you choose.

9. Apr 13, 2013

### technician

I have a ball 15cm diameter, wherever I place a compass, outside the ball, the compass points away in a radial (as far as I can tell) direction.
How close am I to meeting your requirement?

10. Apr 13, 2013

### milesyoung

If this is true regardless of how far out I place the compass, then you're describing the field produced by a magnetic monopole.

11. Apr 13, 2013

### mrspeedybob

Your bar magnet idea will result in a non-magnetized sphere because all the fields will cancel out.

Your ring magnet comment is more interesting. If you take a 2 dimensional cross section of the ring magnets field which is parallel to the plane of the magnet but not centered, the field as it is observable within the 2 dimensional cross section will appear to be a monopole.

Now if you can create a magnet in the shape of a 4 dimensional torus you might get a magnetic field that looks like a monopole along a 3 dimensional cross section.

In order to do this you will have to either find a universe with 4 special dimensions or make your magnet small enough to use one of the dimensions that are curled up very small (assuming that they actually exist.

12. Apr 13, 2013

### technician

I forgot to mention that I ignored Earth's magnetic field but assumed that would be realised. The effects due to the Earth's magnetic field have nothing to do with the effects of my special ball.

13. Apr 13, 2013

### technician

deleted my response

Last edited: Apr 13, 2013
14. Apr 13, 2013

### milesyoung

No worries, my answer assumed the only contribution was from your ball.

15. Apr 13, 2013

### technician

deleted my response

Last edited: Apr 13, 2013
16. Apr 13, 2013

### mrspeedybob

Your experiment is flawed. It may be that you haven't been thorough in mapping your field or it may be that you compass is flawed.

17. Apr 13, 2013

### milesyoung

If you can produce that ball of yours (a magnetic monopole) then my god yes, I'll throw all the money I can scrounge up at you.

18. Apr 13, 2013

### technician

deleted respons

Last edited: Apr 13, 2013
19. Apr 13, 2013

### technician

deleted respons

Last edited: Apr 13, 2013
20. Apr 13, 2013