He did say there are other practical limits to how small it can be though. You have to stuff other stuff inside the coils and the plasma has to be physically separated from the walls of the chamber by some distance since it is so hot it would melt the walls, and it just gets hard to squeeze everything in there. But I wonder for example if SPARC could be made in to a system that could operate continuously, even though ARC makes more sense from a power generation perspective.