Will an oscillating magnetic field penetrate a stainless steel tube?

AI Thread Summary
An oscillating magnetic field can penetrate a stainless steel tube, but its effectiveness depends on factors like frequency, tube configuration, and field geometry. Eddy currents generated in the tube may attenuate the AC field, particularly at higher frequencies. The conductivity of the stainless steel and the presence of conductive water inside the tube also influence penetration. Testing with a permanent magnet yielded positive results, suggesting that a low-frequency oscillating field may perform similarly. Understanding these variables is crucial for successful implementation.
marson
Messages
2
Reaction score
0
I am a chemical engineer, not a physicist, so I am a bit rusty on my electromagnetics.

I need to set up a fluctuating magnetic field inside of a stainless steel tube (hopefully using a pair of electromagnets outside the tube), and I am wondering if the field will penentrate through the tube. I imagine that within some frequency range of oscillation the tube will act as an antenna, but assuming I am below that frequency, will it work?

The tube has 10mm ID and 1mm wall thickness and contains water.

Thanks in advance for any input.
 
Physics news on Phys.org


The tube may attenuate the AC field due to eddy currents, depending on the tube configuration, field geometry, and frequency. If the field is transverse, the calculation is non-trivial. If it is axial, approximate formulas are available. You'll need to know the conductivity of the metal (this can be looked up if you know the stainless's type designator). If the water is conductive (saline), that will affect things as well.
 


Thanks for the info. I set up a simple test with a permanent magnet, and it works just fine. So, I am hoping that with a field oscillating at sufficiently low frequency I will get similar behavior.
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
Back
Top