 Powerful magnetic fields cause large metal rings (likely made of lithium, where a set for one pulse has a total mass of 365 grams) to collapse around the deuterium-tritium plasma, compressing it to a fusion state.Energy from these fusion reactions heats and ionizes the shell of metal formed by the crushed rings.The hot, ionized metal is shot out of a magnetic rocket nozzle at a high speed (up to 30 km/s).