No, it doesn't. Dedicated EMP devices are self contained. You're thinking of the mechanism that converts high-energy gamma rays to an EMP in the aftermath of a nuclear fireball, which requires both an atmosphere (to convert the gamma into high energy electrons) and a wide area magnetic field. That will also apply here, but in the sense of creating a big secondary EMP for the antimatter explosion equivalent to that of a fusion device of the same size.Adrian Laguna wrote:First-off an EMP requires an atmosphere,
Optimum altitude for EMP production is about 30km, but it works well right up into the exosphere. I got the impression the fighter was down in the troposphere when it went up.but the writing suggests that there isn't (atmosphere and orbit are kind of mutually exclusive).
It isn't 'easy'. It's a solved problem, but a fairly expensive one.Second, though, and most important, is the fact that hardening against EMP is pretty easy with modern technology, let alone future tech.
It may be a particle beam (possibly with exotic sci-fi particles) that interferes with electronics, but there's another possibility; the antimatter may be contained by a superconducting magnet system. In the interests of saving weight, this was likely being run at quite close to the critical magnetic field density at which it stops superconducting. An intense EMP might not fry the electronics or directly breech containment by physically moving the antimatter, but it could easily trip a runaway quench in the superconducting rings, that would rapidly result in a containment failure.Therefore one concludes that the Poles were using a device colloquially called "EMP" and that functions similar to an EMP against unhardened electronics, but is actually not EMP but rather [technobable] that works using [technobable].
Incidentally the 'only 75% efficient because lots of the matter didn't react' only works if the ship was really high up. The fact cosmic rays (a fair chunk of which are relativistic particles) don't penetrate the lower atmosphere illustrate how little chance antimatter has of escaping from a low-altitude reaction. However, even with near-total anhiliation a substantial portion of the energy will be lost as neutrinos, so that efficiency is still probably ok for a low-altitude burst.
EDIT: Scratch '30km', turns out I was thinking of the optimum altitude for the second stage energy conversion. The optimum altitude for an EMP-producing fusion or A/M device is rather higher;
