With its tangle of pipes and pumps leading to a metal pot the size of a five-storey building, Japan's JT-60SA machine looks to the untrained eye like a contraption from 1970s sci-fi.
But inside it is a doughnut-shaped vessel where experiments done at millions of degrees could help unlock a carbon-free, inexhaustible and safe power source for the future: nuclear fusion.
"Fusion energy, the power behind the Sun and the stars, has been a great prize for energy research for decades, ever since it was first attempted in the 1950s and 60s to find some way to reproduce this power of the Sun here on Earth," project leader Sam Davis told AFP on a recent tour.
