Unlimited energy may be closer as fusion 'star' experiments advance

Recent progress in tokamak experiments — including reports that China's EAST reactor surpassed the Greenwald density limit and the arrival of ITER's final central solenoid module in France — reflects coordinated gains in fusion science, materials research and computing, while significant technical and economic challenges remain.

Scientists report renewed progress across fusion research that narrows the gap toward practical fusion energy. Tokamak experiments worldwide have extended plasma confinement times and explored higher densities. This month China's EAST reactor reportedly exceeded the Greenwald limit, a theoretical barrier for plasma density. At the same time, large projects and new research centers are assembling key components and investigating materials and control methods needed for sustained operation. Key developments: - China's EAST reactor reportedly surpassed the Greenwald plasma density limit this month. - Testbed tokamaks such as WEST, KSTAR and EAST have extended plasma confinement to hundreds of seconds or a few dozen minutes. - The sixth and final module of ITER's central solenoid arrived in France this past September as part of continued assembly work on the international reactor. - MIT announced the Laboratory for Materials in Nuclear Technologies (LMNT) in June 2025 to accelerate materials discovery for fusion reactors. - Private-sector investment in fusion rose from about $1.5 billion (2016–2020) to nearly $9 billion (2021–2025), according to the Kleinman Center for Energy Policy. - Researchers are exploring artificial intelligence tools to model plasma behavior and support reactor control. Summary: These developments show coordinated progress across experiments, materials research and computing that could inform efforts to demonstrate sustained net energy from fusion in larger test reactors. ITER is positioned to integrate international findings and test feasibility at scale, while programs such as MIT's LMNT focus on materials able to withstand reactor conditions. Major scientific, engineering and economic challenges remain, and precise timelines for commercial deployment are uncertain.