What is Fusion?

Fusion is the energy process that powers the sun and other stars. The fusion reaction between deuterium and tritium produces helium and a neutron with a high energy level, which can be used to heat the steam cycle of a power station for generating electricity. This process is so powerful that the fusion of all atoms in one litre of deuterium-tritium gas mixture would create roughly enough energy to cover the yearly needs of an average-sized house.

To make fusion happen, the positively charged nuclei have to be provided with enough kinetic energy (and thus high speed) to ensure they can overcome their mutual electrostatic repulsion at the time of collision. To achieve this high level of kinetic energy, a hot gas (plasma) has to be heated to a very high temperature of over 100 million degrees, which fuses nuclei together. While the sun's gravity is able to "hold" the hot plasma, on Earth, magnetic fields are needed to confine the plasma.


Since the 1950s, scientists have been investigating different ways to confine the plasma with magnetic fields. In magnetic fusion, the plasma is in a ring-shaped container called "Torus", where strong magnetic fields keep it away from the walls. The "Tokamak" configuration, upon which JET and ITER are based, has been the most successful yet.

The so-called  "Stellarator" is an alternative concept to the Tokamak. Due to its complex magnetic field, the construction of this device is highly challenging, but this design is in principle suitable for continuous (=non-pulsed) operation. The experimental device Wendelstein 7-X has recently been completed and is operated by the Max-Planck Institute for Plasma Physics in Greifswald.

Fusion Device Information System (FusDIS)

The Fusion Device Information System (FusDIS), created by the International Atomic Energy Agency (IAEA), offers an overview of experimental fusion devices worldwide. Currently operated fusion devices as well as those closed, in the planning stage or under construction are marked on a world map. You can refine your search by using various filters.

Further information

Among others, you can find further information on these websites:

Information material may also be requested from the Coordination Office "Fusion @ ÖAW".