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.