KSTAR is a superconducting tokamak, which is a doughnut-shaped machine that uses powerful magnets to trap gas in extreme heat in a state of matter called plasma. Korea’s “artificial sun” broke its own record during a plasma operation in which temperatures of 100 million degrees Celsius were supported for 48 seconds, a promising new step toward nuclear fusion.

The Korea Superconducting Tokamak Advanced Research or KSTAR had previously set a record of reaching 100-million-degree plasma for 30 seconds in 2021, the Korea Institute of Fusion Energy (KFE) said in a statement.

Nuclear fusion happens when two light atoms’ nuclei merge to form a single heavier one, generating a huge release of energy.

This phenomenon powers stars, including the sun, which is why KSTAR has been nicknamed an “artificial sun”. For stars, this process happens due to a massive gravitational force which creates a crushing pressure in the core keeping the nuclei close enough for fusion to occur.

However, achieving fusion on Earth is extremely challenging. It requires recreating the extreme conditions of temperature and pressure found in stars.

Several installations are investigating the possibility of achieving it such as KSTAR.

KSTAR serves as a pilot for the France-based International Thermonuclear Experimental Reactor (ITER). The “artificial sun” provides information that will help better understand fusion.

Currently, the goal of KSTAR is to improve performance to achieve the goal of “300 seconds of plasma operation with ion temperatures over 100 million degrees,” according to KFE. 

In 2023, a part of the tokamak called divertors was upgraded using tungsten. Used to extract heat and ash produced by the fusion reaction protecting the surrounding walls, the new divertors showed only a 25 per cent increase in surface temperature under similar heat loads.

According to the euronews