South Korea’s “artificial sun” has set a new fusion record after superheating a plasma loop to 180 million degrees Fahrenheit (100 million degrees Celsius) for 48 seconds, scientists have announced.
The Korea Superconducting Tokamak Advanced Research (KSTAR) reactor broke the previous world record of 31 seconds, which was set by the same reactor in 2021.The breakthrough is a small but impressive step on the long road to a source of near-unlimited clean energy.
Scientists have been trying to harness the power of nuclear fusion — the process by which stars burn — for more than 70 years. By fusing hydrogen atoms to make helium under extremely high pressures and temperatures, so-called main-sequence stars convert matter into light and heat, generating enormous amounts of energy without producing greenhouse gases or long-lasting radioactive waste.
But replicating the conditions found inside the hearts of stars is no simple task. The most common design for fusion reactors — the tokamak — works by superheating plasma (one of the four states of matter, consisting of positive ions and negatively charged free electrons) and trapping it inside a donut-shaped reactor chamber with powerful magnetic fields.
Keeping the turbulent and superheated coils of plasma in place long enough for nuclear fusion to happen, however, has been a painstaking process. Soviet scientist Natan Yavlinsky designed the first tokamak in 1958, but no one has ever managed to create a reactor that is able to put out more energy than it takes in.
