Measuring Magnetic Field Strength of a Cylindrical Magnet

In summary, the conversation is about quantifying the strength of the magnetic field created by a permanent cylindrical magnet. The speaker has found equations for the field within the z axis, but is interested in knowing the strength in the transverse direction. They mention a reference from Wolfram Alpha which suggests using a numerical approach due to the complicated nature of the calculation. The speaker also asks about the behavior of the field at a very long distance, and the other person responds that it can be approximated using a dipole with a magnitude of 1/r^3.
  • #1
PhDnotForMe
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Hello,
Today I am wondering if anyone can help me quantify the strength of the magnetic field created by a permanent cylindrical magnet. I have been able to find equations online for the strength of the field within the z axis, (ie. the longitudinal length) but I would like to know the strength of the magnetic field in the transverse direction, or the strength of the magnetic field in the outward direction rather than on top or below.
 
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Likes PhDnotForMe, vanhees71 and anorlunda
  • #3
Pythagorean said:
A cylindrical magnet is finite and, therefore, has edging effects. It's not a straightforward calculation, but Wolfram Alpha briefly touches the calculation superficially (and notes that the guts are complicated) favoring a numerical approach.

http://demonstrations.wolfram.com/MagneticFieldOfACylindricalBarMagnet/
Thanks for that great reference. The equations listed are pretty intense. If you considered a point in the transverse direction REAALLY far away, and the length and diameter of the magnet are small in comparison, would the strength of magnetic field be roughly proportionate to 1/R^2? 1/R? 1/R^3? The integral listed in the reference is way to difficult for me to estimate the macro-behavior.
 
  • #4
At a very long distance (compared to the extension of the magnet) you can use the leading-order multipole, which in this case is a dipole. The magnitude goes like ##1/r^3##.
 

1. How do you measure the magnetic field strength of a cylindrical magnet?

The magnetic field strength of a cylindrical magnet can be measured using a Gaussmeter or a Hall probe. These devices measure the strength of the magnetic field in units of Gauss or Tesla.

2. What is the difference between the magnetic field strength and magnetic flux density of a cylindrical magnet?

Magnetic field strength refers to the force exerted by a magnetic field on a unit magnetic pole, while magnetic flux density refers to the amount of magnetic flux passing through a unit area. In other words, magnetic field strength measures the intensity of the magnetic field, while magnetic flux density measures the density of the magnetic field lines.

3. How does the shape of a cylindrical magnet affect its magnetic field strength?

The shape of a cylindrical magnet does not have a significant impact on its magnetic field strength. However, the length and diameter of the magnet can affect the distribution of the magnetic field around it.

4. What factors can affect the accuracy of measuring the magnetic field strength of a cylindrical magnet?

The accuracy of measuring the magnetic field strength of a cylindrical magnet can be affected by the distance between the magnet and the measuring device, the orientation of the magnet, and any external magnetic fields that may interfere with the measurement.

5. Can the magnetic field strength of a cylindrical magnet be changed?

Yes, the magnetic field strength of a cylindrical magnet can be changed by altering the material it is made of, the number of turns in its coil, or the current flowing through the coil. It can also be affected by external factors such as temperature and mechanical stress.

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