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     China’s “artificial sun” reactor has broken its own world record for maintaining super-hot plasma. This marks another milestone in the long road towards near-limitless clean energy.
     The Experimental Advanced Superconducting Tokamak (EAST) nuclear fusion reactor maintained a steady, highly confined loop of plasma for one thousand sixty-six seconds (eighteen minutes) on January 20th, 2025. This more than doubled its previous best of four hundred seconds. (seven minutes).
     Nuclear fusion reactors are nicknamed “artificial suns” because they generate energy in a way that is similar to the Sun by fusing two light atoms into a single heavy atom via heat and pressure. The Sun has a lot more pressure than Earth’s fusion reactors, so scientists compensate by using temperatures that are many times hotter than the Sun
     Nuclear fusion offers the potential of a huge power source without greenhouse gas emissions or much nuclear waste. However, scientists have been working on this technology for more than seventy years, and it is probably not progressing fast enough to be a practical solution to the climate crisis. Researchers expect us to have commercial fusion power plants within decades, but it could take much longer.
     EAST’s new record won’t immediately usher in what is dubbed the “Holy Grail” of clean power. However, it is a step towards a possible future where commercial fusion power plants generate electricity.
     EAST is a magnetic confinement reactor, or tokamak, which is designed to keep the plasma continuously burning for prolonged periods. Fusion reactors like this have never achieved ignition, which is the point at which nuclear fusion creates its own energy and sustains its own reaction. However, the new record is a step towards maintaining prolonged, confined plasma loops that future commercial fusion reactors will need to generate electricity.
     Song Yunta is the Director of the Institute of Plasma Physics responsible for the fusion project at the Chinese Academy of Sciences. He said, “A fusion device must achieve stable operation at high efficiency for thousands of seconds to enable the self-sustaining circulation of plasma, which is critical for the continuous power generation of future fusion plants.”
     EAST is one of a growing number of nuclear fusion reactors worldwide, but they all currently use far more energy than they produce. In 2022, the U.S. National Ignition Facility’s fusion reactor briefly achieved ignition in its core using a different experimental method to EAST. It relied on quick bursts of energy, but the reactor as a whole still used more energy than it consumed.
     Tokamaks like EAST are the most common research nuclear fusion reactors. EAST heats up plasma and traps it inside a donut-shaped reactor chamber with powerful magnetic fields. For the latest Chinese EAST record, researchers made several upgrades to the reactor, including doubling the power of its heating system.
     The data gathered by EAST will support the development of other fusion reactors, both in China and internationally. China is part of the International Thermonuclear Experimental Reactor (ITER) program. This project involves dozens of countries, including the U.S., U.K. Japan, South Korea and Russia.
     The ITER reactor, which is being built in southern France, contains the world’s most powerful magnet and will be operational in 2039 at the earliest. ITER is an experimental tool designed to create sustained fusion for research purposes, but it could pave the way for commercial fusion power plants. Song said, “We hope to expand international collaboration via EAST and bring fusion energy into practical use for humanity.”

Experimental Advanced Superconducting Tokamak

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