Editor’s note: This question was asked in response to Interference Technology’s recent webinar by Keith Armstrong. To view the webinar, click here.
Question: Skin depth concept seems to mean that currents of same direction in conductor will repel each other to the surface of conductor which seems to contradict to the concept of currents of same direction will attract each other?
Answer: Currents flowing in the same direction do actually repel each other, because their magnetic fields are in the same orientation.
As I understand it, this is exactly what causes the skin effect to occur for currents and their associated magnetic fields (and vice-versa).
This is exactly the same as two bar magnets repelling each other when they are aligned the same way around – so their North poles are facing each other, and so are their South poles.
Currents flowing in opposing directions attract each other, because their magnetic fields are in opposite directions and so tend to cancel out, reducing the energy in the system, which is what Nature is always trying to achieve.
This is exactly the same as two bar magnets attracting each other when they are aligned the opposite way around – so the North pole of one faces the South pole of the other, and vice versa.
See Richard Feynmans’s book, in my reply to the first question, for why (in this universe!) Nature always acts to reduce the energy in a system by as much as possible. Without this no electric generators or motors would work as they do, nor much else!
-Keith Armstrong
