Fusion is simple — practically primitive — whereas plasma physics is insanely-mind-numbingly difficult. To sustain a fusion process, plasma physics have to be

Fusion is simple — practically primitive — whereas plasma physics is insanely-mind-numbingly difficult. To sustain a fusion process, plasma physics have to be tamed. That's the hard part. The Wendelstein 7-X, which the article is about, can't even do fusion, it's entirely about plasma physics.