same, up to 30K Isp (vasimir engine, most advanced ion drive right now)
It's more about the limits of the engine than the power source if you're applying polywell fusion to it
EM is, for all intensive purposes (
), a grav inertial drive. basically...it's hard as **** to explain, and also sounds crazy and you'll call me an idiot for discussing it.
Anyway, it would allow for a goodly amount of near light speed travel (i think .2c)
maybe i'm getting confused...It's discussed in detail by guys who are actually running the experiements on some site i visit. They'll know more in a few years as well (2).
I'll re-read up on that drive, and Bussard's engine as well since he had designed a spaceship already using his power source