Hey, guys. There is something interesting about the skin effect, which also made me curious. Could you please help to solve it? The following is what I got from Wiki. It is said that, according to theory of induction, induced current would oppose the change of magnetic field. Then when current increases in the upward direction, the outward induced current would be formed. However, when current decreases in the upward direction (you know this is AC current), then it seems induced current would change into inward direction so as to maintain magnetic field. If it is the case, the "skin effect" would change into "core effect". However, why does this never come true?