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Electromagnetism: Magnetic Field, change in permeability

  1. Jun 18, 2015 #1
    Hello everyone.

    I've built a Helmholtz coil and I'm attempting to understand how the magnetic field direction and magnitude will be effected do to a material with a particular permeability.

    In the first picture I have an infinitely long cylinder with a particular thickness and permeability. There is a coil around the chamber. My Helmholtz coils are some distance from the chamber. I'm trying to find out how the B or H field is effected by the chamber due to its permeability and thickness. There are three areas that I'm concerned about. I was able to solve this for the center of the coil without the chamber using Biot Savart. I'm not sure what happens when a material is added in between.

    In the second picture I have an infinitely long piece of square strut. The is a coil around the strut. The strut is off center to the coil. The strut has a particular height and width. I'm trying to find out how the be field is effected within the coils due to the piece of strut.

    Is there a particular section in Jackson or Griffiths that would help me understand this problem? I'm assuming dB/dt = 0 as my coils have been turned on and running for some time.

    Thanks to anyone who could provide some insight to this problem.

    Attached Files:

  2. jcsd
  3. Jun 18, 2015 #2


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    Staff: Mentor

    The cylinders in the sketch have infinite length, the coils do not (just two with zero length each)? I'm quite sure that needs a numeric simulation.
  4. Jun 19, 2015 #3
    Assume just one coil in a plane. I'm pretty sure this will require a numeric simulation as well.

    I found an example in Jackson that gives some insight to this problem. I have a CAD model of this. Is there is a free solver somewhere for a problem like this?
  5. Jun 20, 2015 #4
    Have you access to any code solving the Laplace equation in 2D?
    You should as a student. I can give you links if you need.
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