In 1951, together with Andrei Sakharov, Tamm proposed a tokamak system of the realization of CTF on the basis of toroidal magnetic thermonuclear reactor and soon after the first such devices were built by the INF, resulting the T-3 Soviet magnetic confinement device from 1968, when the plasma parameters unique for that time were obtained, of showing the temperatures in their machine to be over an order of magnitude higher than what was expected by the rest of the community.

where denotes the characteristic scale of the system, for example is the minor radius of the torus in a tokamak.

This has advantages relative to the more conventional deuterium-tritium ( D-T ) reaction of other confinement and compression devices such as the tokamak or inertial confinement fusion ( ICF ) devices that amplify and focus multiple high-energy beams of lasers, electrons or ions onto tiny pellets of D-T fuel.

In 1950 he also proposed an idea for a controlled nuclear fusion reactor, the tokamak, which is still the basis for the majority of work in the area.

It is much harder to design a divertor ( the section of the wall that receives the exhaust power from the plasma ) in a stellarator, the out-of-plane magnetic coils ( common in many modern stellarators and possibly all future ones ) are much harder to manufacture than the simple, planar coils which suffice for a tokamak, and the utilization of the magnetic field volume and strength is generally poorer than in tokamaks.

A tokamak is a device using a magnetic field to confine a plasma in the shape of a torus.

In a tokamak, the toroidal field is produced by electromagnets that surround the torus, and the poloidal field is the result of a toroidal electric current that flows inside the plasma.

The tokamak is one of several types of magnetic confinement devices, and is one of the most-researched candidates for producing controlled thermonuclear fusion power.

An alternative to the tokamak is the stellarator.

The word tokamak is a transliteration of the Russian word токамак, an acronym of either " тороидальная камера с магнитными катушками " ( toroidal ' naya kamera s magnitnymi katushkami )— toroidal chamber with magnetic coils, or " тороидальная камера с аксиальным магнитным полем " ( toroidal ' naya kamera s aksial ' nym magnitnym polem )— toroidal chamber with axial magnetic field.

In the ITER tokamak, it is expected that the occurrence of a limited number of major disruptions will definitively damage the chamber with no possibility to restore the device .< ref > Wurden, G., ( 2011 ) International Workshop " MFE Roadmapping in the ITER Era ", Princeton < http :// advprojects. pppl. gov / Roadmapping / presentations / MFE_POSTERS / WURDEN_Disruption_RiskPOSTER. pdf ></ ref >< ref > Baylor, L. R .; Combs, S. K .; Foust, C. R .; Jernigan, T. C.

In current tokamak ( and other ) magnetic fusion experiments, insufficient fusion energy is produced to maintain the plasma temperature.

It appears that the maximum plasma temperature attainable by ohmic heating in a tokamak is 20-30 million degrees Celsius.

This is a large advantage of tokamak reactors since these freed neutrons provide a simple way to extract heat from the plasma stream ; this is how the fusion reactor generates usable energy.

The most widely studied configuration for terrestrial fusion is the tokamak, a form of magnetic confinement fusion.

In the advanced tokamak and ST, wall stabilization is critical for operation with a large bootstrap fraction.

The NTM is already an important performance-limiting factor in many tokamak experiments, leading to degraded confinement or disruption.

as demonstrated in tokamak experiments, and rotational shear is also predicted to stabilize resistive

The western scientists visited the experiment and verified the high temperatures and confinement, sparking a wave of optimism for the prospects of the tokamak as well as construction of new experiments, which is still the dominant magnetic confinement device today.

* 2006-China's EAST test reactor is completed, the first tokamak experiment to use superconducting magnets to generate both the toroidal and poloidal fields.

Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and: DEMO.

Because of the extremely high power requirements for the tokamak, and the fact that power draw from the main grid is limited, two large flywheel generators were constructed to provide this necessary power.

As of 1998, a higher Q of 1. 25 is claimed for the JT-60 tokamak ; however, this was not achieved under real D-T conditions but extrapolated from experiments performed with a pure deuterium ( D-D ) plasma.

In 1968, at the third IAEA International Conference on Plasma Physics and Controlled Nuclear Fusion Research at Novosibirsk, Soviet scientists announced that they had achieved electron temperatures of over 1000 eV in a tokamak device.

progress has been achieved with a particular emphasis on the tokamak.

Sakharov, in association with Igor Tamm, proposed confining extremely hot ionized plasma by torus shaped magnetic fields for controlling thermonuclear fusion that led to the development of the tokamak device.

The tokamak provides the required twist to the magnetic field lines not by manipulating the field with external currents, but by driving a current through the plasma itself.

Experimental research of tokamak systems started in 1956 in Kurchatov Institute, Moscow by a group of Soviet scientists led by Lev Artsimovich.

These neutrons, being electrically neutral, are no longer held in the stream of plasma by the toroidal magnets and continue until stopped by the inside wall of the tokamak.

One might attempt to circumvent the problem by confining the fission fuel magnetically, in a manner similar to the fusion fuel in a tokamak.

* 1950-An idea of nuclear fusion reactor tokamak was proposed by soviet scientists Andrei Sakharov and Igor Tamm.

* 1956-Experimental research of tokamak systems started at Kurchatov Institute, Moscow by a group of Soviet scientists led by Lev Artsimovich.

* 1968-Results from the tokamak, a T-3 Soviet magnetic confinement device, which Igor Tamm and Andrei Sakharov had been working on, shows the temperatures in their machine to be over an order of magnitude higher than what was expected by the rest of the fusion community.

Hundreds of fusion scientists and engineers in each participating " country " took part in a detailed assessment of the then present status of the tokamak confinement concept vis-a-vis the requirements of an EPR, identified the required R & D by early 1980 and produced a conceptual design by mid-1981.

At the Geneva summit meeting in 1985, Secretary Gorbachev suggested to President Reagan that the two countries jointly undertake the construction of a tokamak EPR as proposed by the INTOR Workshop.

The Levitated Dipole Experiment was funded by the United States Department of Energy's Office of Fusion Energy, but funding for the LDX and other alternative fusion projects was ended in November 2011 to concentrate funding on tokamak approaches.

It was followed by the NSTX spherical tokamak.

MAST uses the same innovative spherical tokamak design as START, which has shown itself to be more efficient than the conventional toroidal design, adopted by JET and ITER.

In spite of these early successes, by the late 1980s the tokamak had surpassed the confinement times of the spheromaks by orders of magnitude.

In fact, the very large diameter of the next generation tokamak implies that it will be very difficult to mitigate the disruptions that pose a significant challenge in future tokamaks where the increased stored energy can lead to unacceptably large transient heat loads on plasma facing components.

The fusion reactions in the plasma spiraling around a tokamak reactor produce large amounts of high energy neutrons.

" The leading designs for controlled fusion research use magnetic ( tokamak design ) or inertial ( laser ) confinement of a plasma, with heat from the fusion reactions used to operate a steam turbine which in turn drives electrical generators, similar to the process used in fossil fuel and nuclear fission power stations.

* 1998-The JT-60 tokamak in Japan produced a high performance reversed shear plasma with the equivalent fusion amplification factor of 1. 25-the current world record of Q, fusion energy gain factor.

Internal view of the JET tokamak superimposed with an image of a plasma taken with a visible spectrum video camera.

* GYRO, a computer program for tokamak plasma simulation

: Subj: Diagnosis of plasma shape within the tokamak fusion machine using reconstructions based upon EPI.

Unlike the stabilized pinch devices in the US and UK, the tokamak used considerably more energy in the stabilizing magnets, and much less in the plasma current.

* A mechanism for magnetically limiting a plasma, and hence for controlling the nuclear fusion in a tokamak

In the tokamak a current is periodically driven through the plasma itself, creating a field " around " the torus that combines with the toroidal field to produce a winding field in some ways similar to that in a modern stellarator, at least in that nuclei move from the inside to the outside of the device as they flow around it.

The extensions off the top and bottom are plasma flowing to the ring diverters, a key feature of modern tokamak designs.

Spheromaks have also been used to inject plasma into a bigger magnetic confinement experiment like a tokamak.

This is similar to the field configuration of a tokamak, except that the field-producing coils are simpler and do not penetrate the plasma torus.