It is an artistic, yet quite accurate 3D model of a tokamak type fusion reactor.

The inner diameter of the fusion chamber is ~12m, which is about the size of "ITER".  

Info:

Modell:                    TOKAMAK fusion reactor
Blender version:     2.91.2
Render Engin:         Cycles (Main) / Eevee
Polycount:               ~800K per segment (6) 
Extra:                       Unwrapped
           
Additional Information:

There are two scenes.

In the first scene is the funsion reactor.

In the second is a shader that simulates small plasma stripes.

In the collection "Plasma" the plasma is blended with a boolean of a surface - this can slow down the viewport!