In 2026, South Korea's KSTAR tokamak sustained a plasma at over 100 million degrees for more than 100 seconds — a world record demonstrating the viability of long-pulse, steady-state fusion operation.
In 2026, the Korea Superconducting Tokamak Advanced Research (KSTAR) facility achieved a landmark in fusion plasma physics by sustaining a plasma at ion temperatures exceeding 100 million degrees Celsius for more than 100 seconds. This result set a new world record for high-temperature plasma duration in a tokamak and demonstrated critical capabilities needed for steady-state fusion power plants.[1]
A commercial fusion power plant must operate continuously or in very long pulses to deliver reliable baseload electricity. While many experiments have achieved the temperatures and densities needed for fusion, sustaining these conditions for extended periods introduces additional physics and engineering challenges: plasma instabilities must be actively controlled, heat must be continuously exhausted, and the plasma current must be driven non-inductively. KSTAR's 100-second milestone demonstrated integrated solutions to all of these challenges simultaneously.[2]
KSTAR is uniquely suited for long-pulse experiments because it uses superconducting magnets (niobium-tin and niobium-titanium) that can operate indefinitely without resistive heating losses. Unlike copper-magnet tokamaks, which are limited to pulses of a few seconds by coil heating, KSTAR's superconducting coils enable the extended operations needed to study steady-state plasma physics. The device has a major radius of 1.8 meters and operates with advanced plasma shaping and heating systems.[3]
KSTAR's results feed directly into the physics basis for ITER, which is designed to sustain burning plasmas for 300 to 500 seconds. The Korean achievement validates key operational scenarios planned for ITER and demonstrates that the plasma control tools developed over the past two decades are mature enough for long-duration high-performance operation.[2]