Fusion is the process which powers the sun and other stars. The fusion reaction between deuterium and tritium produces helium and a neutron with a high energy which can be used to heat the steam cycle of a power station for generating electricity. The fusion of all the atoms in one liter of a deuterium-tritium gas mixture would create roughly enough energy to provide the yearly needs of an average size house.
To make fusion happen, a hot gas (plasma) has to be heated to over 100 million degrees which fuses nuclei together. In the sun it is gravity that “holds” the hot plasma. On Earth, magnetic fields are needed to confine the plasma.
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.