The magnets that are enough to lift the aircraft carrier are now completed, marking a critical milestone in the pursuit of harnessing the power of the star. Iter, a sprawling international fusion energy project in southern France, has completed all components to become the world’s largest and most powerful pulsed superconducting electromagnetic system.
The last piece of the electromagnetic puzzle was delivered in April 2025, when General Atomics completed the sixth module of the central solenoid valve – a giant cylindrical magnet that will form the heart of the donut-shaped fusion reactor of Iter, called tokamak.
When fully assembled, this pulsed magnet system will weigh 3,000 tons and produce a magnetic field 280,000 times stronger than the Earth. The fields will create an “invisible cage” to heat plasma to 150 million degrees Celsius, ten times higher than the core of the sun.
“Iteration projects are a manifestation of hope,” Barabaschi said. “With ITER, we demonstrate a sustainable energy future and a path to peace.”
“What makes Iter unique is not only its technological complexity, but also maintaining its international cooperation framework by changing the political landscape,” said Pietro Barabaschi.
The project represents an unusual geopolitical achievement: ongoing cooperation between China, Europe, India, Japan, South Korea, Russia and the United States. The seven members contributed components manufactured in hundreds of factories on three continents to build a machine.
Engineers designed the support structure of the central solenoid valve to withstand twice the force that the space shuttle launches. The entire system needs to be cooled to -269°C with liquid helium to maintain superconductivity.
This achievement was achieved as ITER reaches 100% of its construction targets, and most of the major components are now delivered. In April 2025, workers arranged the first vacuum vessel module into the Tokamak pit in advance, marking another important step.
When running, the ITER aims to generate 500 MW of fusion power from an input heating capacity of only 50 MW – a ten times the energy gain will prove the survivability of the fusion as a power supply.
Fusion works by combining hydrogen isotopes to form helium, which releases huge energy (the same reaction as our sun powers). Unlike current nuclear power, fusion does not produce long-term radioactive waste and uses seawater-rich fuel.
The completion of the magnet system represents years of precision engineering in multiple countries. The United States built a central solenoid valve and its support structure. Russia provides a 9-meter-diameter ring field magnet for the top of Tokamak. Europe produces four multi-type field magnets in France, ranging in diameter from 17 to 24 meters. China has created a 10-meter-long magnetic field magnet that has been installed at the bottom of a partially assembled Tokamak.
Japan produces superconductor chains for the central solenoid valve and eight ring magnetic field magnets. The thermal shield produced in South Korea distinguishes ultra-hot plasma from ultra-cold magnets. India made a 30-meter-high cryostat – essentially a huge thermos, which houses the entire Tokamak.
Raw materials alone are surprising: over 100,000 kilometers of superconducting chains are manufactured in nine factories in six countries. Once completed, ITER’s magnet system will store 51 Gigajoules of energy.
As investment in the private sector surges in Converged Energy Research, iteration launched an initiative in 2024 to share its accumulated knowledge. In April 2025, the organization chaired a public-private seminar to address collaborations that address the remaining technical challenges of Fusion.
“Iteration projects are a manifestation of hope,” Barabaschi said. “With ITER, we demonstrate a sustainable energy future and a path to peace.”
After completion of the fusion experiment, it will serve as a large-scale research laboratory in its member states, providing critical data to optimize commercial converged power plants in the coming decades and potentially provide carbon-free energy with unlimited fuels.
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