This startup is developing tiny 'benchtop' fusion devices in secret to build a more efficient nuclear reactor

Nuclear fusion is how stars (including our own Sun) create their energy, and scientists are hopeful it could one day be used as a clean, abundant energy solution here on Earth. There are no carbon emissions, most of the fuel required is widely available, and it's safe: if the reaction goes wrong, it simply peters out and stops.

You might have spotted the big challenge, which is trying to fit an entire star's worth of energy production inside a power…