If our regular huge power plants on the ground could be used to power part of a rocket launch, launch mass would be smaller since fuel would not have to be carried on board. I wonder what are the main weaknesses and problems with this? How could it be done, if at all?
One limit of electric ion engines seems to be that it requires quite a huge electric power plant to match the effect generated by the explosion in a chemical rocket engine. But with a reusable first stage ion electric engine which is physically connected to the electric grid on the ground, I imagine that one could turn up the power until the cable glows and electric effect is not the limit anymore.
Another limit might be how large an ion engine can be in terms of gas mass flow per second, or how many small ones that can be bunched together. Maybe lifting the cable is a problem, even if it is put on the ground/sea surface under the planned launch trajectory, because one would have to reach a substantial fraction of the escape speed in order for this to be worthwhile.
Are there other electric rocket engine types which would work better than ion engines when very high electric effect is available?