I’ve seen the prototype in operation, in person. Beautiful magenta plume, and a great concept. Basically, how much thrust you produce depends on how much power you can bring to bear. The magnetic field generated deflects a great deal of interplanetary radiation, and the constant thrust generates a gravity frame of reference.
Great Stuff!
What I couldn’t find was what kind of terminal velocity they could get out of it. Wiki only has “ultra fast deep space transport” as one of it’s attributes.
It does sound like it will be much faster than the engine driving the probe to Pluto at 10 miles per second.