A tokamak is a device which uses a powerful magnetic field generated by external magnets to confine plasma in the shape of an axially-symmetrical torus. The tokamak is one of several types of magnetic confinement devices being developed to produce controlled thermonuclear fusion power. The tokamak concept is currently one of the leading candidates for a practical fusion reactor.
The reaction chamber of the DIII-D, an experimental tokamak fusion reactor operated by General Atomics in San Diego, which has been used in research since it was completed in the late 1980s. The characteristic torus-shaped chamber is clad with graphite to help withstand the extreme heat.
A USSR stamp, 1987: Tokamak thermonuclear system
Ronald Richter (left) with Juan Domingo Perón (right). Richter's claims sparked off fusion research around the world.
Red plasma in EAST, with visible light radiation dominated by the hydrogen alpha line emitting 656 nm light.
Plasma is one of four fundamental states of matter characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. It is the most abundant form of ordinary matter in the universe, mostly in stars, but also dominating the rarefied intracluster medium and intergalactic medium.
Plasma can be artificially generated, for example, by heating a neutral gas or subjecting it to a strong electromagnetic field.
Lightning as an example of plasma present at Earth's surface: Typically, lightning discharges 30 kiloamperes at up to 100 megavolts, and emits radio waves, light, X- and even gamma rays. Plasma temperatures can approach 30000 K and electron densities may exceed 1024 m−3.
Artificial plasma produced in air by a Jacob's Ladder
Hall-effect thruster
Plasma spraying