The first attempts to build a practical fusion machine took place in the United Kingdom, where George Paget Thomson had selected the pinch effect as a promising technique in 1945. After several failed attempts to gain funding, he gave up and asked two graduate students, Stan Cousins and Alan Ware, to build a device out of surplus radar equipment. This was successfully operated in 1948, but showed no clear evidence of fusion and failed to gain the interest of the Atomic Energy Research Establishment. In 1948, Yavlinsky moved to the Kurchatov Institute. By this time, other Soviet scientists under Kurchatov such as Nobel Prize laureates Andrei Sakharov and Igor Tamm were working on the Soviet atomic bomb project. As for Yavlinsky, who was given his own laboratory in the institute, he was tasked to develop power supply systems. It did not take long before he also became involved in nuclear research. After developing the bomb, Sakharov and Tamm began work on the tokamak system in 1951. A tokamak is a device that uses a powerful magnetic field to confine a hot plasma in the shape of a torus. The tokamak is one of several types of magnetic confinement devices being developed to produce controlled thermonuclear fusion power. The word tokamak is a transliteration of the Russian word токамак, an acronym of either:
"тороидальная камера с магнитными катушками" — toroidal chamber with magnetic coils; or
"тороидальная камера с аксиальным магнитным полем" — toroidal chamber with axial magnetic field.
The term was attributed to Igor Golovin. Sakharov and Tamm completed a much more detailed consideration of their original proposal, calling for a device with a major radius of and a minor radius of. The proposal suggested the system could produce of tritium a day, or breed of U233 a day. However, Yavlinsky and another scientist, Golovin, considered developing another model focusing on more static toroidal arrangement. It was the development of the concept now known as the safety factor that guided tokamak development; by arranging the reactor so this critical factor q was always greater than 1, the tokamaks strongly suppressed the instabilities that plagued earlier designs. Yavlinsky's model led to the creation of T-1, the first real tokamak, in 1958. The T-1 used both stronger external magnets and a reduced current compared to stabilized pinch machines like ZETA. Yavlinsky was already preparing the design of an even larger model, later built as T-3, the first large tokamak. With the apparently successful ZETA announcement, Yavlinsky's engineering concept became viewed as more acceptable. For his work on "powerful impulse discharges in a gas, to obtain unusually high temperatures needed for thermonuclear processes," he was awarded the Lenin Prize and the Stalin Prize in 1958. Despite this success, Kurchatov asked Yavlinsky to develop a stellarator instead of finishing the T-3. Besides, as of 1961, the succeeding installation known as the T-2 began showing issues in the toroidal circuits. Nevertheless, Yavlinsky's design prevailed as other Soviet scientists began to favor the tokamak and persuaded Kurchatov to leave the stellarator research to the Americans.
Death
Yavlinsky was not to see the T-3 completed. On 28 July 1962, while travelling from Lviv to Sochi through Aeroflot Flight 415, he and his family died in an airplane crash at Gagra. While there has been speculation that his death was connected with politics, primarily over his intended developments in nuclear research, the government did not provide any clear indication that this was so. Despite his death, the T-3 was finished, and began to show successful results in compensating the inadequacies of other systems, including the stellarator, by 1965. The T-3 had then surpassed the Bohm limit ten times. Three years later, when the Soviets had achieved two main criteria in achieving nuclear fusion, namely the temperature level and the plasma confinement time, the so-called tokamak stampede had reached the United States.
