Skin effect is the phenomenon where:

Skin effect is a phenomenon that occurs in conductors carrying alternating current, particularly at radio frequencies (RF) and beyond. As the frequency of the current increases, the distribution of the current density within the conductor becomes non-uniform. Instead of flowing evenly throughout the entire cross-section of the conductor, most of the current tends to flow near the surface. This behavior arises because, at higher frequencies, the alternating magnetic fields generated by the current induce opposing currents within the conductor, effectively pushing the primary current towards the outer layer, or "skin," of the material. This results in the current primarily occupying a thin layer of the conductor rather than its full volume, leading to the term "skin effect."

Understanding skin effect is crucial for designing efficient radio frequency circuits, as it impacts the effective resistance and performance of conductive materials at high frequencies.