hi,
I am sorry, but could you explain, please? You said that maximum current is about 100000A. As I know, the diameter of wire may be (approximately) calculated as:
(1,27*I/A)^0,5. For pulse working, the density of current (A) is about 5A/mm², now calcualte:
SQR(1,27*100000/5)~=159mm.
Well, I may try to imagine such copper wire let say 12 meters long (but I doubt that somebody is able to move it rare than Schwarzenegger :)
But: I cannot imagine the electrode: with diameter 16cm it may not be called "spot".
Are you sure about values?

Thanks,
Oleg