How a San Diego magnet may unlock the future of clean energy
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A magnet so powerful it could lift an aircraft carrier might sound like science fiction. In San Diego, it is science at work. General Atomics recently shipped the first section of the Central Solenoid, a superconducting magnet bound for ITER, the world’s largest fusion reactor under construction in France. When fully assembled, the solenoid will rise as tall as a five-story building and form the heart of an experiment designed to solve one of humanity’s most urgent challenges: creating limitless clean energy.
Why fusion energy has long been the ultimate prize
Fusion occurs when atomic nuclei collide and merge under extreme heat and pressure, releasing vast amounts of energy. It is the same reaction that powers the sun. Unlike nuclear fission, which splits atoms and produces long-lived radioactive waste, fusion has no risk of meltdown and generates only short-lived byproducts. Its fuel sources, deuterium and tritium, are available in seawater and lithium.
The appeal of fusion is clear: it offers a nearly limitless, clean, and safe energy source. If commercialized, it could meet global electricity demand without the carbon emissions driving climate change. It would also provide reliable baseload power that solar and wind cannot always deliver. For decades, researchers have called fusion the “holy grail” of energy, but until recently, it has remained out of reach.
Building the magnetic bottle to contain a star on Earth
The Central Solenoid is designed to solve one of fusion’s central challenges: keeping plasma hot and stable long enough to sustain energy-producing reactions. Plasma, a superheated state of matter where electrons break free from atoms, can reach temperatures above 150 million degrees Celsius. No physical material can contain it.
That is why ITER relies on magnetic confinement. The Central Solenoid acts as the spine of ITER’s magnetic bottle, producing an electromagnetic field strong enough to control and shape the plasma without letting it touch the reactor walls. Each of its six modules weighs nearly 250,000 pounds. Together, they will generate magnetic forces that could lift entire naval vessels.
The engineering demands are immense. The magnet relies on superconducting materials cooled to near absolute zero so that electric currents can circulate without resistance. This allows the device to generate fields far stronger than ordinary magnets without overheating. Building and transporting such a structure has taken years of design, testing, and precision manufacturing at General Atomics.
ITER and the global effort to achieve first plasma
ITER, based in southern France, is the largest scientific collaboration on Earth. More than 30 countries, including the United States, China, Japan, Russia, and members of the European Union, are pooling expertise and funding. Its mission is to demonstrate that fusion power can be sustained at a scale that makes commercial plants feasible.
The project’s timeline has shifted. First plasma, initially targeted for 2025, is now projected for 2034. The delay stems from the pandemic, quality control problems with unique components, and the difficulty of assembling the first-of-its-kind machine. Despite these setbacks, ITER remains the most ambitious attempt yet to prove the viability of fusion as a large-scale energy source. The Central Solenoid is central to this effort. Without it, ITER’s plasma could not be stabilized. Its successful installation will mark a milestone toward the facility’s eventual operation.
Recent breakthroughs and rising momentum in fusion research
Progress is not limited to ITER. Around the world, laboratories and startups have been pushing boundaries. In Germany, the Wendelstein 7-X stellarator has set records for plasma performance and duration, showing new ways to keep fusion reactions stable. In France, the WEST tokamak has achieved sustained plasmas lasting several minutes. At the National Ignition Facility in California, scientists have repeated experiments producing more energy output than input, reaching more than 8 megajoules in some shots.
Financial momentum is growing too. Global investment in fusion energy rose by $2.64 billion in 2025, the largest increase in years. In total, nearly $10 billion has flowed into private fusion companies since 2021. Governments are also stepping up. The United Kingdom pledged £410 million to accelerate research, while German authorities signed agreements with startups to build pilot plants by the mid-2030s.
These developments illustrate a key point: fusion is no longer confined to distant theory. It is advancing on multiple fronts, from large multinational projects to private ventures.
The challenges between promise and power plant reality
Despite the momentum, commercial fusion power remains at least a decade away. The obstacles are as daunting as they are varied. Plasma stability over long durations remains difficult to achieve, as does managing the materials exposed to extreme heat. A commercial reactor will also need a sustainable tritium fuel cycle, which has yet to be proven at scale.
Then there is the cost. ITER alone is expected to cost tens of billions of dollars by the time it reaches operation. Private companies estimate that billions more will be required to move from demonstration reactors to commercial plants. For investors and governments, the risk is that fusion takes longer to arrive than current enthusiasm suggests.
Public perception is another factor. Fusion is often portrayed as just around the corner, but the history of missed deadlines has created skepticism. Advocates must balance optimism with transparency about the remaining challenges.
General Atomics’ role in building the Central Solenoid highlights how regional expertise feeds into global innovation. San Diego has long been a hub for advanced energy and defense research, and its contributions to ITER place it at the center of a project with worldwide implications.
When ITER powers up in the 2030s, the magnet built in San Diego will be one of the reasons it works. Beyond the technical achievement, the project underscores the value of collaboration between industry, government, and international partners in solving problems too large for any single nation.
For now, the Central Solenoid represents both the weight of scientific challenge and the pull of potential reward. If successful, it will not only stabilize plasma inside a reactor but also help stabilize the world’s energy future.
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