The Farnsworth–Hirsch fusor, or simply fusor, is an apparatus designed (~1964) by Philo T. Farnsworth to create nuclear fusion. It has also been developed in various incarnations by researchers including Elmore, Tuck, and Watson, and more recently by George H. Miley and Robert W. Bussard. Unlike most controlled fusion systems, which slowly heat a magnetically confined plasma, the fusor injects "high temperature" ions directly into a reaction chamber, thereby avoiding a considerable amount of complexity. The approach is known as inertial electrostatic confinement (IEC).
Hopes at the time were high that it could be quickly developed into a practical source of fusion power. However, as with other fusion experiments, development into a generator has proven to be difficult. Nevertheless, the fusor has since become a practical source of free neutrons, and it is produced commercially for this purpose. Fusors have been assembled in low-power forms by hobbyists.
Read more about Fusor: History, Basic Fusion, Fusor Fusion, Power Density, Thermalization of The Ion Velocities, Electrodes, Bremsstrahlung, Use As A Neutron Source, Patents