I
Indirect drive
A laser driven fusion method in which a sphere of fusion fuel is compressed indirectly by X-rays generated after the lasers hit the inner wall of the metal cavity. The target, a sphere containing frozen hydrogen, is suspended on plastic filaments inside a metal cylinder called a hohlraum. Powerful laser beams aim through holes in the ends of the cylinder at its inner wall. It starts to emit powerful X-rays that fills uniformly the whole cavity. The radiation pressure then compresses the target to the levels needed for thermonuclear fusion. The indirect drive approach provides more uniform compression of the target surface while having lower requirements for precise laser targeting.