KSTAR fusion device maintains 100 million degrees for record 20 seconds KSTAR fusion device maintains ... KSTAR, the so-called "Korean artificial sun," has set a record for maintaining plasma at temperatures over 100 million °C 1/1 KSTAR, the so-called "Korean artificial sun," has set a record for maintaining plasma at temperatures over 100 million °C While harnessing the power of the Sun has progressed in leaps and bounds in recent years, harnessing the process that powers the Sun is proving a tough nut to crack. However, progress continues to be made on the various approaches to practical nuclear fusion being pursued, of which tokamak reactors remain a frontrunner. In another promising development for the technology, the Korea Superconducting Tokamak Advanced Research (KSTAR) fusion device has set a world record by maintaining plasma at over 100 million °C (180 million °F) for 20 seconds.