Physicist: The weapon itself doesn’t cause the EMP (or not much
of one). The pulse is actually generated by the weapon’s effect
on the Earth’s ionosphere. An EMP is just a sudden change in the
electric and magnetic fields, which on its own isn’t too bad. It
doesn’t hurt people at least. However, changing EM fields induce
currents in anything capable of carrying a current. This is
especially true of power lines, where the current can really
“build up some steam”. The problem with current suddenly showing
up where it’s not expected is that it can arc or overload
circuits. The kind of components and wiring you find in today’s
electronics (and the last 30 some odd years) can be destroyed by
the sort of sudden surge you get from regular old static
electricity. Of course because of that, sensitive electronics
are generally grounded (with ground lines!) and/or shielded with
Faraday cages. The way you generate an EMP (or any interesting
electromagnetic effect) is you get a bunch of charge and
suddenly move it. A nucl