Scientists have achieved a major milestone in fusion research: they sustained an artificial sun burning inside a machine for 102 seconds.
South Korea’s KSTAR fusion reactor (Korea Superconducting Tokamak Advanced Research) successfully maintained high-performance plasma at 100 million °C (180 million °F), roughly seven times hotter than the core of the Sun, for a record 102 seconds in high-confinement (H-mode) operation. This more than doubled the device’s previous performance in just a few years.
Fusion is the same process that powers the Sun and stars: it merges light atomic nuclei to release vast amounts of energy. If harnessed on Earth, it could provide nearly limitless clean electricity with no carbon emissions and minimal long-lived radioactive waste, often called the “holy grail” of energy.
The main challenge is controlling plasma, a superheated state of matter so energetic that no physical container can hold it. Scientists use powerful magnetic fields inside doughnut-shaped tokamaks to suspend and contain it.
KSTAR’s breakthrough came after upgrading its divertor (the component that handles the most intense heat) to tungsten. This new fully tungsten-lined interior allowed the reactor to sustain stable high-confinement plasma for 102 seconds, the first time it achieved this duration in the new configuration.
While KSTAR does not yet produce electricity, every extra second of stable operation yields critical data for future fusion power plants. The team’s next ambitious target is to maintain these extreme conditions for 300 seconds.
[Korea Institute of Fusion Energy (KFE) official announcements and campaign results (2024)]