General Atomics starts winding operations on fusion magnet

US firm General Atomics (GA) has started construction on one of the most important components of ITER, the experimental nuclear fusion reactor currently being built in the South of France: the huge superconducting electromagnet that will sit at the centre of the doughnut-shaped reactor. Called the Central Solenoid (CS), it will weigh 1,000 tonnes when completed, making it among the most powerful magnets ever built and one of the heaviest single components of ITER.

The CS has two roles in ITER: its 13.1T magnetic field (some 500 times stronger than the magnetic field at the Earth’s surface) will keep the electrically-charged plasma inside ITER away from its inner walls, and will also help set up a current that will keep the charged particles of the plasma circulating around the reactor. The solenoid, which is made of six stacked modules, will store some 5.5 gigajoules of energy: enough to lift the aircraft carrier USS Gerald Ford, which weighs around 100,000 tonnes.