It's a newly proposed fusion reactor prototype. It's a stellerator type reactor. Together with the Tokamak type reactor these two are the currently most promising types to achieve fusion and generate more energy than they take to operate. While the tokamakak type looks more symmetrical to the human eye the stellerator types have adopted very weird looking shapes where the symmetries are more hidden. The pictures are from this paper by mostly people from the institute who created the to date biggest stellerator type fusion generator Wendelstein 7-x. Their proposed prototype 'Stelaris' is a lot bigger than the 7-x.
Bonus (with little context):
And heres a shematic view oft how it would look like from outside. Just like a donut.
I decided to read up on it since it looks a bit mental but once you know why it makes a lot of sense.
Plasma is charged and needs to be contained with magnets because it'll melt anything it touches.
To use the magnets uniformly on a donut shaped cloud of particles will cause the particles drift and hit the wall because the donut has particles traveling short distences close to the donut hole and long on the rim. The particle will eventually drift into the wall and destroy the reactor.
So fuck it, squash the donut and twist it around and now all of parts of a cross section traveling around the donut are traveling equally long distance.