What is a Tokamak?
A tokamak is a toroidal plasma confinement device invented in the 1950s by the Russians Tamm and Sakharov (yes, the famous one). The word “tokamak” is a contraction of the Russian words: “toroidalnaya”, “kamera”, and “magnitnaya”, meaning “toroidal chamber-magnetic.” The plasma is confined here not by the material walls (which wouldn’t be compatible with a plasma which will be millions of degrees Celsius), but by magnetic fields. Physicists have been working since the 1950s on making better “magnetic bottles,” a problem which has been compared to holding jello (the plasma) with rubber bands (the magnetic field). The magnetic fields in a tokamak are produced by a combination of currents flowing in external coils and currents flowing within the plasma itself. This contrasts to a similar concept, the stellarator, in which all of the confining magnetic fields are produced by external coils.
A tokamak is a toroidal (doughnut-shaped) magnetic plasma confinement device, the leading candidate for producing magnetic fusion energy. The term tokamak comes from the Russian words: “toroidalnaya”, “kamera”, and “magnitnaya”, which mean “toroidal, chamber, magnetic”. The last letter g was replaced by k to avoid analogy with the word magic. It was invented in the 1950s by Igor Yevgenyevich Tamm and Andrei Sakharov. The tokamak is characterized by the use of the plasma current to generate the helical component of the magnetic field necessary for stable equilibria. This can be compared to another toroidal magnetic confinement device, the stellarator, in which all of the confining magnetic fields are produced by external coils and there is a negligible current flowing through the plasma. Why doughnut shaped? The distinctive shape of the fusion reactor is necessary because of a particular property of a doughnut that a sphere (for example) does not have. Essentialy the problem is the hair
