How do you build the world's largest magnet? It's complicated

THE SUPERCONDUCTING E ELECTROMAGNET IS THE 'BEATING HEART' OF THE ITER TOKAMAK- A MAGNETIC CONFINEMENT DEVICE THAT PRODUCES CONTROLLED THERMONUCLEAR FUSION POWER.

THE WORLD'S LARGEST AND MOST POWERFUL magnet, the 'Central Solenoid', is finally here or at least, the first piece of it is. Fully assembled, it will be 18 m tall, 4 m wide, and weigh about 910 metric tons, meaning the decade-in-the-making magnet will be truly massive. Appropriately, it will find a home in southern France at the world's largest fusion reactor, the International Thermonuclear Experimental Reactor (ITER), this year.

Constructing a magnet of this magnitude is one huge job. Engineers and technicians at General Atomics in San Diego have spent more than half a decade designing, fabricating, and testing the various components of the Central Solenoid in its production facility-and that's only half the battle. Transporting each piece of the magnet is a Herculean endeavour in and of itself, requiring custom-built roads and cranes to haul them.

It makes sense when you consider the scope of the magnet. 'If you think about an aircraft carrier, which weighs... about 100 million kg, the Central Solenoid will generate enough magnetic force that it would be able to lift it 1.8 m into the air,' says John Smith, director of engineering and projects for General Atomics.

In August 2021, the magnet's first module arrived in France, but the Central Solenoid will eventually consist of six pieces in total. Each module is 2.1 m tall, 4.2 m wide, and 114 000 kg. Once complete, engineers will stack and link the modules together at the centre of the reactor.