Out in Sorrento Valley, past a security gate and a plain industrial front, San Diego researchers are lighting up what they say is the hottest place in the entire solar system. Inside, a doughnut-shaped machine called a tokamak spins a ribbon of superheated plasma that briefly mimics the physics inside a star. Students, university teams and private companies all make the trip to test ideas they hope will shape the future of commercial fusion power.
According to Axios, General Atomics officials say the DIII‑D tokamak can hit temperatures "100 times hotter than the sun." Director Richard Buttery told the outlet that the lab’s long‑term goal is to help build a fully operational fusion pilot plant by 2030. The Axios visit puts the Sorrento Valley machine in the same conversation as recent national fusion milestones and a wave of investor interest in the technology.
What the machine actually is
A tokamak is a ring-shaped fusion reactor that uses powerful magnetic fields to trap plasma until hydrogen isotopes fuse and release energy. The U.S. Department of Energy describes DIII‑D as the largest magnetic fusion research experiment in the country and as an Office of Science user facility that backs the physics work needed for future tokamaks, according to DOE. Its measurements and diagnostics help teams test stability, heating and exhaust strategies that feed into larger fusion projects around the world.
A hub for hundreds of researchers
General Atomics says the DIII‑D program works with more than 800 researchers from universities, national labs and private industry. Recent upgrades were designed to speed data sharing with major supercomputing centers. That "superfacility" setup, which links DIII‑D experiments to NERSC and ESnet, is intended to let remote teams analyze experimental shots in near real time and widen participation in the program, per General Atomics.
How DIII‑D fits into the national push
Federal reviews and watchdog reports point to fusion research as a growing priority for U.S. science funding, with DIII‑D repeatedly singled out as a central test bed for tokamak physics. A recent GAO review highlighted ongoing investments and the role of user facilities in moving toward eventual commercialization. Data from the Department of Energy also underscore that user counts and program scope at facilities like DIII‑D have grown over the last decade, drawing in public and private collaborators who see the lab as a way to reduce risk on next‑generation designs.
What it means for San Diego
For San Diego, DIII‑D serves as a high-profile example of the region’s dense technical ecosystem, from semiconductors to biotech, that can host large science projects and employ skilled technicians and engineers. The DIII‑D program also runs outreach and tour efforts during industry events, and facility leaders say continued upgrades will be vital if the United States wants to turn experimental advances into pilot-scale systems, according to DIII‑D's own materials.
Whether these tiny, controlled "suns" in Sorrento Valley will deliver commercial electricity in the next decade is still an open technical and economic question. For now, the DIII‑D tokamak keeps San Diego in the center ring of a fast-moving national race to harness fusion power.
