I What causes skin effect in AC currents?

AI Thread Summary
The skin effect in AC currents causes electrons to concentrate near the surface of a conductor rather than the center. This phenomenon occurs because the alternating magnetic field around the wire generates a current that creates an opposing magnetic field, which reduces the magnetic field penetrating the conductor. As a result, the current predominantly flows along the outer surface. In contrast, DC currents do not exhibit this behavior, as they do not create the same alternating magnetic fields. Understanding the skin effect is crucial for applications involving high-frequency AC currents.
Qmavam
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My assumption has been it is the electromagnetic field starting from the center of the wire that pushes the electrons outward.
However, this would also be true of a DC current, but it isn't.
So why does an AC current cause electrons to move toward the skin of a wire?
I don't recall ever seeing this explained.
Thanks, Mikek
 
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Qmavam said:
So why does an AC current cause electrons to move toward the skin of a wire?
It does not.
The current starts on the outside surface, and moves slowly into the conductor.

The incident loop of magnetic field, around the wire, causes a current to flow along the wire.
That causes an opposite magnetic field loop, that cancels most of the incident field, which reduces the magnetic field entering the conductor, and so the current stays on the surface.
 

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