60 years ago, when nobody knew anything about fusion (so not a very different situation from today...), the stellarator was the favored design. The advantages

60 years ago, when nobody knew anything about fusion (so not a very different situation from today...), the stellarator was the favored design. The advantages are obvious on paper (which is all they had back then): continuous operation, more stable plasma. But then the Russians built a small tokamak and it worked surprisingly well. So the whole world went "given the importance of fusion, shouldn't the time and effort being put into stellarators be devoted to something that's important in the immediate?" and started working on tokamaks. 60 years later, tokamaks still haven't been turned into power plants. Things were harder than imagined, and much more expensive, too. It doesn't look as if ITER will ever yield something practical. Maybe the MIT guys can make the Arc Reactor a reality; but all they have right now is... exactly, paper. (The whole world? No! A tiny village outside Munich built the Wendelstein series of stellarators...)