Yup, EMP has been on my list since it was a classified phenom. (Hawaii found out about it, following a hi alt. [!!] explosion we sent up over the Pacific simply because we could.) Kids with bitchin bottle rockets..

Our blas\ufffd attitude all along, even among people should have known -- can be underscored, ex: the US military snickers at the vacuum-tube electronics in a [particular] MIG, long after we'd gone to a billion transistors/item. It never occurred then to our scoffers, Why this "old tech" was used by this apparently primitive bunch o Kulaks [hyuk hyuk].

Of course, not just anyone [this week..] can launch an appropriately-sized device over say, Omaha - 'appropriately' in the sense of there being little ground effect, accurate elevation, etc.

Some (few) things, mostly military were hardened early-on. (And even the term 'hardness' was classified). Probably most critical military comms are, by now. I've noted the near complete blackout on this phenom for so long, I think I concluded that it would remain just too unpleasant to get past the filters, given how easily our comfort-obsessed sheep are panicked.

What's it about? (think you know this; some may not) Well.. just look up the breakdown voltage in volts/M in air. Then imagine an almost "delta function": a point value with 0 risetime, in electronic parlance. OK - can't quite be 0; think a few picoseconds and a voltage near to the breakdown value for air. Remember that a square wave is approximated by a Fourier series of sinewaves and you get radiated in a sphere:

Most RF freqs. up into multiple GHz spewed; lots of things would act as antennas at various of these -- but instead of a few tens of \ufffdV/M RF field, imagine many KV/M. Consumer-grade transistor devices, even with a little 'surge protection' == instant toasted junctions. Pimptillions of them.

Etc.


Add-to-List of dangling swords.
Bon appetit