The documents about lightning surges I have say there are significant common mode and differential parts. Additionally, my experiments in LTspice indicate that the currents can be in the 100A ballpark, which would make a CMC rather huge. The high voltage across the windings would also require TIW, so the dimensions inflate again.
An air core 500uH/3A single inductor made of 1mm TIW would be about the size of a matchbox. Can you make a reliable CMC of comparable size?
I like this idea. Even a modest amount of L, but replicated sufficiently many times should slow down the lightning dI/dt to a survivable level. Thanks, Win!
Best regards, Piotr