Fusion is hard. I thought of another use for that laser: Take a small cylinder of pyrolytic graphite (it is diamagnetic, repelled by magnets) milled to be in t

Fusion is hard. I thought of another use for that laser: Take a small cylinder of pyrolytic graphite (it is diamagnetic, repelled by magnets) milled to be in the ideal axis and polystyrene layered in it. Then shoot it into a somewhat large ring of powerful magnets that have a trough in them to such a degree that it can trap the cylinder as it accelerates around the loop. The cylinder is propelled by successive shots of laser bursts that are not powerful enough to ablate (but close). One of the electromagnets can be quickly deactivated to allow for the cylinder to escape. Then it travels for a safe distance into very large lead target. Fusion could proceed if the speed is fast enough as the fuel is inertially kept together and friction should raise it’s temperature. If it produces neutrons, they will be absorbed by the lead. You can just collect the heat. Edit. I think the lead target would be a no go. It would be no different than a bullet hitting a soft block of lead. Better would be a block of silicon carbide with some kind of borehole made of tungsten metal with fuel packed at the end of it. So the rice sized cylinder of nuclear fuel shoots right into the borehole and before the material can squeeze itself out, it has to overcome the enormous inertia keeping it going in one direction. Might be better though if the target itself was fuel. And it would be much easier to fuse lithium dueuteride than hydrogen and carbon. I seem to recall a recent story on HN about something similar. So it isn't really a new idea. Perhaps making it run a circular course is different or that it doesn't use ablation for propulsion, it uses light pressure. I think the project was in the UK.