Direct drive
Laser-driven fusion method, in which lasers beam from all sides and simultaneously strike the surface of a sphere of frozen fusion fuel, which is then compressed by their energy to the temperature and density needed to ignite thermonuclear fusion. The surface of the sphere, containing a frozen mixture of deuterium and tritium, evaporates when the laser beams hit it. Due to the law of action and reaction, the interior of the sphere is enormously compressed. When sufficient temperature and density are reached, a fusion reaction takes place in the centre of the sphere. The fuel residue is then blown apart by inertia. The problem with the direct-drive method is the uneven compression of the target, which is why the indirect-drive method is currently more widely used.