Fission is a chain reaction, Fusion is not. A fusion reaction is so unstable that if the reactor failed the conditions for sustaining fusion would immediately stop.
It's basically the hottest plasma we can make suspended in a magnetic donut surrounding by near absolute zero temperatures.
It's basically the hottest plasma we can make suspended in a magnetic donut surrounding by near absolute zero temperatures.
https://en.m.wikipedia.org/wiki/Tokamak