Tokamaks are one of the most widely studied technologies in the global effort to achieve sustained nuclear fusion. Using intense magnetic fields, they confine superheated plasma within their doughnut-shaped interiors, allowing atomic nuclei to fuse together and release vast amounts of energy. Tokamaks are one of the most widely studied technologies in the global effort to achieve sustained nuclear fusion. Using intense magnetic fields, they confine superheated plasma within their doughnut-shaped interiors, allowing atomic nuclei to fuse together and release vast amounts of energy. Plasma Physics Phys.org – latest science and technology news stories