Tokamak

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TOKAMAK Info

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A tokamak is a machine producing a toroidal (doughnut-shaped) magnetic field for confining a plasma. It is one of several types of magnetic confinement devices and the leading candidate for producing fusion energy.

The term Tokamak is a transliteration of the Russian word Токамак which itself comes from the Russian words: "тороидальная камера в магнитных катушках" (toroidal'naya kamera v magnitnykh katushkakh) — toroidal chamber in magnetic coils (Tochamac)). It was invented in the 1950s by Soviet physicists Igor Yevgenyevich Tamm and Andrei Sakharov (who were in turn inspired by an original idea of Oleg Lavrentyev).

The tokamak is characterized by azimuthal (rotational) symmetry and the use of the plasma current to generate the helical component of the magnetic field necessary for stable equilibrium. This can be contrasted to another toroidal magnetic confinement device, the stellarator, which has a discrete (e.g. five-fold) rotational symmetry and in which all of the confining magnetic fields are produced by external coils with a negligible current flowing through the plasma.