The helium plasma - a cloud of loose, charged particles - lasted just a tenth of a second and was about one million degrees Celsius.
It was hailed as a breakthrough for the Max Planck Institute's stellarator - a chamber whose design differs from the tokamak fusion devices used elsewhere.
The Sun's energy is created by fusion.
Physicists are in a worldwide race to create stable fusion devices that could not only mimic the Sun but release abundant energy, without the volumes of toxic waste generated by nuclear fission - the splitting of the atom.
