Re: Could a spacecraft use this to push itself?
Not by itself in deep space. You still need a reaction mass. However, I could see using it in certain rare instances, like pushing off from an asteroid or some other large object with a negligible gravitational pull. Assuming electrical power is no object (nuclear, for example,) I could see it saving thruster fuel under those circumstances. One would probably not want to use it to maneuver near a space station, since the station would be joggled around, and the electromagnetic waves would probably fry all the electronics.