Also known as a magnetic fusion drive, or a mega-ion drive.
A staple of high end sci-fi is the replicator or the nano-assembler. There is a much more practical and less technomagical way to achieve the same goal. The exciting thing is that this technology exists now, and we're getting much better at it.
As they travel they notice a horrible rotten smell. As they travel it gets stronger and stronger forcing them to cover their noses and mouth less they choke on the horrible smell. Stream full of dead fish. Spawning trout die in mass quantities after they spawn littering areas with dead fish dying and deteriorating in the sun.