Thermonuclear fusion powers the stars and produces 10 times more energy than fission. Mastering it in Earth conditions would provide an endless source of energy, but many technological challenges have yet to be solved.

The tokamak uses a toroidal magnetic cage to isolate hot plasma from vessel walls. Thermonuclear fusion can be ignited inside after reaching suitable conditions. More than 50 tokamaks are involved in fusion research today.

The idea of a stellarator is based on the premise that plasma can be held in the reaction space by means of a special helically wound magnetic field that is generated exclusively by magnetic coils of various shapes.

Inertial confinement tries to quickly compress the fusion fuel to achieve high temperatures and pressures. Typically, a hydrogen sphere is hit by laser beams directed at its surface or into a cavity called the hohlraum.

Thermonuclear fusion is a clean, safe and almost inexhaustible source of energy. Fusion plant could be based on magnetic or inertial confinement, use deuterium-tritium or aneutronic fusion, and produce own tritium fuel.