Re: The *real* tough part is not nS (or even pS, with the right design) switching, it's the
"Actually if you want to do this is also the old school "Saturatable reactor" tech."
yeah, about mag-amps... they're notoriously inefficient, so they'll heat up really fast. Additionally, you COULD make a mag-amp rectifier, but regardless you still need to feed them with AC, and not DC, which means that charging a bank of super-capacitors and then RAPIDLY discharging them into the railgun system to fire it would be out...
nice try, though. Sorry to pee on your parade, to wet your blanket, to hose you down in your moment of passion, to poop your party, to ...
compare to much smaller (and lower dissipated power) IGBTs and/or MOSFETS. Hell, with optoisolators you could get away with using standard bipolar, or even (if you're really tricky) use SCRs. A few decades back I saw some static inverters that actually used a bank of SCRs in the output stage, big bolty-looking things, several inches in diameter. I think these inverters were designed in the 1970's, long before IGBTs and vertical MOSFETS came around. And they had massive cooling fans, too.
Anyway, there are LOTS of ways to skin cats, remove one's clothing, etc..