Hey all, I'm working on a project now where I am using a solenoid driven at a 10Hz AC current to create a magnetic field on a solid piece of low carbon iron, and then using a smaller solenoid to capture the magnetic flux coming from the iron. By measuring the phase of the resulting waves from the drive coil and the sense coil I notice that the phase difference between the two coils increases as I move the sense coil away from the drive coil. This tells me that there is a measurable delay between the transmission of the magnetic flux into the iron, and when that flux is picked up by the sense coil. It also seems to depend on the distance from the drive coil. Can anyone give me a reason that this might be happening or some theory behind this? I was under the impression that magnetic flux moved at the speed of light, but this might have to do with the magnetic domains aligning as H changes. Thanks!