USING A GIANT L ASER
Despite the laser’s enormous size, all the real action takes place inside a tiny metal cylinder called a hohlraum, which is the German word for ‘cavity’. But this particular cavity is specially designed to contain a nuclear fusion reaction. The hohlraums used in NIF are less than a centimetre in length and half a centimetre in diameter; they house a millimetre-scale target pellet made from a mixture of tritium, deuterium and ordinary hydrogen. When the hohlraum is flooded with high-intensity laser light, the target pellet absorbs all that energy and a sudden burst of nuclear fusion ensues.