Coconut fusion reactor.

New Scientist goes tropical, revealing what a fusion reactor has in common with a pina colada:

The coconuts will be used to generate 10,000 cubic metres of nothing – the vacuum essential to ITER’s operation. Some of this vacuum, in the central chamber, separates the plasma from the surrounding solid walls and allows fusion to proceed unhindered by air molecules. A whole lot more nothing is needed to fill the vacuum jackets that insulate ITER’s supercooled magnets.

“We wanted a material that behaves like a sponge, with lots of internal surfaces,” says Day.

He and his team have spent 20 years searching for the ideal adsorber. Their quest was wide-ranging, taking in sintered metals and porous minerals called zeolites, but eventually they found that the material with the greatest capacity to adsorb gases was charcoal. They tried charcoal made from industrial polymers, from different varieties of wood, from peat, and from textiles such as wool and cotton, and more.

Once source stood out. “We found that coconut-shell charcoal is the best,” Day says. “It is somehow strange that you need this very natural material to make a fusion device.”

Best part: not just coconuts, but coconuts from one Indonesian island. That grew in 2002.