[little jeremiah]

I’ve read about EMP stuff from someone who actually has worked with them and what they can actually do is pretty localized, apparently.

[grey_whiskers]

A few years back, there was some nice discussion here on Starfish Prime.

EMP is dependent not on the energy budget of the weapon,but of the hard X-ray and gamma ray flux, which induces Compton scattering (to near- or mild-relativistic speeds) of electrons which are then directed towards the ground by the Earth's magnetic field.

Moving electrons create magnetic fields; magnetic fields induce short-lived currents in all kinds of electronic circuits.

Major fun ensues.