A stellarator generating a helical magnetic field using one or two helical magnetic coils, supplemented by several poloidal coils. It is a simplified version of the classical stellarator, which can manage without toroidal magnetic coils. The so-called ultimate torsatron does not even have poloidal coils and replaces the vertical field by varying pinch of the helical coils, through which current flows in the same direction. The torsatron was developed in Ukraine. The first torsatron, Saturn-1, started its operation in 1970 at the Kharkov Institute of Physics and Technology. It was followed by several other devices, of which Uragan III was the first torsatron equipped with a divertor. Very similar in design to the torsatron is the Japanese heliotron.