The achievement comes through a combination of factors. The KSTAR group used a completely non-inductive mode and a high-power neutral beam to reach the plasma state, and they reduced the heat on plasma-facing parts through tricks such as creating a spinning 3D field. On top of this, they also developed another groundbreaking, more practical mode that should allow for higher pressure at relatively low temperatures.

You're still a long, long way from seeing practical fusion energy. However, the efforts will help South Korea develop a new reactor, K-DEMO, that should demonstrate the advantages of steady-state fusion power. Think of this as a nudge that gets the ball rolling on a transition toward cleaner, safer and more powerful replacements for the nuclear reactors you see today.