by Vyacheslav STRELKOV, Dr. Sc. (Phys. & Math.), National Research Center "Kurchatov Institute", Moscow, Russia

Last February (2012) Russian nuclear physicists marked the birth centennial of Dr. Nathan Yavlinsky, an eminent research scientist and engineer, a man who stood at the cradle of an innovative trend in science, the controlled thermonuclear fusion (CTF) based on the concept of toroidal setups for magnetic confinement of plasma (known here in Russia and elsewhere as tokamaks). The idea was incubated back in 1951 by Igor Tamm and Andrei Sakharov, members of the national Academy of Sciences, and further conceptualized at the Laboratory of Measuring Instruments (the National Research Institute "Kurchatov Institute" today) headed by Acad. Igor Kurchatov. Nathan Yavlinsky, or Nathan the Wise (as Kurchatov would call him after the name of the protagonist of the philosophical tragedy by the German classic Gotthold Ephraim Lessing) came to the Kurchatov laboratory in 1949 and worked there up until 1962, when he died in an air crash. Yavlinsky headed a large research collective that produced pioneering works on plasma physics.

Nathan Yavlinsky was born on February 13, 1912, into a M.D.'s family. That is, he was of the intellectual background (belonging to the intelligentsia, a social group of Russian intellectuals). Now in the initial Soviet years, after the October Revolution of 1917, an intellectual had to learn a factory worker's trade and become a "proletarian" before going to senior college or university. Yavlinsky did that. Leaving a trade school attached to the Kharkov mechanical works in 1931, the young industrial operative got enrolled in the night department of a college attached to the Kharkovbased elecltrochemical works, and continued his studies while still on the job. Simultaneously he edited the factory newspaper that appeared in Russian, Ukrainian, Yiddish, Latvian and German: many Latvians and Germans worked at that enterprise evacuated from Riga, the Latvian capital city, during the First World War of 1914-1918. While still a junior student, Nathan became chief of one of the factory's design offices. In 1936 Yavlinsky became a certified engineer and soon after entered the Department of Physics at the Kharkov Institute (senior college) of Physics and Engineering taking a correspondence course. He completed only two years. As he later explained it to us, young research scientists, he left because he was a family man and a baby was born to him. But actually there was yet another reason: expelled from the Communist Party, Yavlinsky lost his job at the plant and had to quit the college. The probable cause of the expulsion from the party ranks and dismissal was that the older brother of his wife-to-be was arrested as a Trotskyite*. For about a year Yavlinsky stayed jobless, but then he was readmitted to the Communist Party and regained his old job as design office head.

With the outbreak of the Great Patriotic War in 1941, Yavlinsky volunteered for the front service. His request was granted after a time, though. Appointed director of one of the divisions of the Kharkov electrochemical plant evacuated to the Urals, he was accused of sabotage. But the blitz German offensive killed that false charge. At the front the young soldier and a hundred men were encircled by the enemy. Things were haywire, as Yavlinsky recalled. Finding his bearings on his map, he headed east hacking through woodlands and bypassing population centers. A group of soldiers joined him, and they broke out of the bag.

In 1942 Yavlinsky took part in the Battle of Stalingrad as chief of artillery repair shops. Each night smashed guns were brought to him from the Volga's right bank, the site of the city of Stalingrad and the hot spot of fighting. He managed to organize round-the-clock welding, though it was prohibited for blackout reasons. Yavlinsky said it was his great accomplishment. The Germans used flares so bright that no welding could betray the workshops. Though reprimanded time and again, Yavlinsky was in for official thanks nonetheless. He won.

Recalled from the frontline in 1944, Yavlinsky headed the Central Design Office at the Moscow-based All-Union Electrotechnical Research Institute. That design office was working on new models of military hardware. Yavlinsky was involved with electromagnetic amplifiers there. In 1945 he went on a business trip to Germany to pick out electrotechnical equipment in keeping with the reparation deal obliging Germany to make good the damage inflicted on our country during the war years. In 1949 he merited a Stalin Prize for "designing electrical machines" and assimilating their industrial output.

That year Dmitry Yefremov, director of the Electrosila plant in Leningrad (St. Petersburg today), the largest power-engineering enterprise in this country and simultaneously USSR Deputy Minister of Electrical Engineering, who knew Yavlinsky personally, sent him

* Member of the left-wing opposition of the 1920s and 1930s within party ranks led by Leon Trotsky (1879-1940).--Ed.

to the Laboratory of Measuring Instruments headed by Lev Artsimovich*, an outstanding physicist. Joining hands, they developed an industrial technology for the separation of uranium isotopes and set up power supply systems for separation units. As the Artsimovich department turned to nuclear fusion experiments in 1951, Yavlinsky made a turnabout in changing his priorities in favor of controlled nuclear fusion, CNF.

The first work of the Artsimovich research collective dealt with gaseous discharges. It was published in a collection of articles on plasma physics and controlled thermonuclear reactions. This article and those that followed showed the complexity of experiments in toroidal geometry. Tamm and Sakharov, who conceptualized the CTF idea, suggested a magnetic system in the form of an energized torus ("bagel") for plasma heating and confinement; these two physicists were the first to validate the tokamak idea in theory. The creators of the tokamak setup were Ivan Golovin (1913-1997) and Nathan Yavlinsky. Both, heading two divisions in the Artsimovich department, were involved with thoroidal discharges. While Golovin conceptualized experiments in bare outlines, Yavlinsky took care of their practical implementation.

CTF experiments in the 1950s proceeded in different directions. As far as toroidal systems were concerned, the main experiments were carried out at the magnetic-field torus (MFT) setup built in 1954 to the Golovin and Yavlinsky RFP (request for proposal). This setup was used for studying conditions of discharge initiation and stability, and for assessing electron temperature values.

Late in 1957 the British science journal Nature published a sensational communication on experiments at

* See: Ye. Velikhov, "Thermonuclear Combustion"; V. Strelkov, "No Royal Ride in Thermonuclear Research", Science in Russia, No. 1, 2009.--Ed.

the Zeta setup. British physicists measured the neutron yield and counted the nτ_Ε criterion according to which a positive-yield thermonuclear reaction depends on the product of the density of heated plasma (n) and the time of its cooling, τ_Ε. The results were chocking, though they proved wrong two years later. Be that as it may, the Zeta experiments touched off heated discussions, and were instrumental in expanding hot plasma research in domestic toroidal systems.

Acad. Igor Kurchatov* decided to develop an analogous setup at home promptly. Accordingly, the Alpha setup, a full-scale copy of Zeta, was built in a record time, in just eight months, at the Leningrad Research Institute of Electrophysical Instruments.

Kurchatov urged Artsimovich to rush work and repeat the British experiments. Artsimovich held his ground for a time-he hesitated and was in no hurry. In the spring of 1958 the MFT setup was closed down to be replaced with a system similar to the British. It had an aluminum chamber whose Al₂O₃ oxide layer could play a part in the plasma/wall interaction-the spectacular Zeta results had possibly something to do with that. It proved a dud, however: manufactured at an aviation plant, the torus leaked since the vacuum tightness of seams happened to be faulty, and the machine was out of whack.

Yavlinsky, meanwhile, was building a T-1 setup that went down in the history of nuclear research as the first tokamak. It confirmed the Kruskal-Shafranov criterion (stability of high-current plasma in the magnetic field) named after Martin Kruskal (USA) and Vitaly Shaf-ranov (Russia), two scientists eminent in theoretical physics. These experiments involved a limiting diaphragm, used for the first time to contain the plasma column (pinch), a device now common at many setups. T-1 made measurement of radiation losses, the principal channel of plasma losses, with more than 80 percent in the region of vacuum ultraviolet.

The Yavlinsky division designed and built an electronic computer. Unlike other computers of those days, it needed no round-the-clock servicing. Nathan Yavlinsky and Gleb Dolgov-Savelyev got down to calculations of

* See: Ye. Velikhov, "He Dreamt of a Sun on Earth". Science in Russia, No. 1, 2003.--Ed.

power losses through the lineate emission of plasma impurities. Actually this was the beginning of work on computer simulation of tokamak plasma processes.

The emission of plasma impurities was found to take a significant amount of energy out of hot plasma. Thereupon Yavlinsky turned to building a new setup, T-2, containing the prototypes of functional elements of subsequent tokamaks, such as high-vacuum evacuation, double vacuum and an all-metal headed chamber. Nonetheless this system was not recognized as the only acceptable version of a thermonuclear setup. After the Second Geneva Conference on the Peaceful Uses of Atomic Energy (1958) our nuclear physicists were of two minds: what kind of setup should be built at the Kurchatov Institute for large-scale CNF experiments: a stellarator* or a tokamak? Yavlinsky, Stanislav Braginsky and Vitaly Shafranov opted for tokamaks as more promising ("Comparison of the Stellarator and Tokamak Systems", December 1958). Kurchatov decided to build T-3, Europe's largest. Yavlinsky and coworkers were in the know about the macroscopic stability of the pinch, they proved that the radiation losses due to the linear-like emission of impurity ions were playing a substantial part in the plasma power balance, while the component of stray magnetic fields, transverse relative to the plasma current, had a cardinal effect on the pinch equilibrium.

I hate to use the pat phrase-"done under his guidance", for it is false and sanctimonious. Yavlinsky was one of us, the heart and soul of a large collective of physicists and engineers. As in 1958 world laboratories declassified works on CTF, it became clear that we were the "globe's leaders" not in the ballet alone. A group of nuclear physicists, Yavlinsky among them, with Lev Artsimovich at the head, were awarded a Lenin Prize for "research into powerful pulse discharges in gas for obtaining high-temperature plasma".

The T-3 setup was commissioned in 1962, after Yavlinsky's tragic death. His pupils carried on. By the mid 1960s we achieved a real breakthrough: the plasma confinement time was found to be close to 20 ms, or tenfold longer than the commonly prognosticated "Bohmian time" calculated from the empirical formula deduced by David Bohm, an American physicist, in the late 1940s. The same machine registered a thermonuclear neutron radiation of a stable plasma loop. That is to say, the T-3 setup built at Yavlinsky's initiative triggered the world's first controlled thermonuclear reaction, CTR.

An engineer by the grace of God, he could say right away: This device will work, and that will not. Yavlinsky was a great physicist who kept learning, nonstop.

* A magnetic trap with closed surfaces. Unlike the tokamak, the stellarator generates a poloidal magnetic field in outer coils. The stellarator idea was advanced by Laiman Spitzer of the United States in 1951. The first stellarator was installed at the Princeton Laboratory of Plasma Physics, USA.--Ed.

Science in Russia, No.4, 2012

Dr. Ksenia Razumova, one of his best pupils, explained why Nathan Yavlinsky was called "Nathan the Wise". "While going ever deeper into physics, his forte, he worked hard to build a collective. Therein lay his wisdom. Building it brick by brick, he got a monolith, an envy even to the tightest of families... This collective lived on after Yavlinsky's death and became a crystallization nucleus for newcomers."

He had this to say about Lev Artsimovich in charge of the Soviet CTF program. "Lev Artsimovich is a good physicist. He will always help you and explain the nuts and bolts of physics. But as to managerial matters, you better do without him." Yavlinsky acted accordingly. When necessary, he got in touch with Kurchatov and government officials. He never said "You should do it"-he understood what they "could and could not do", and made the best of this stance. Artsimovich did not mind. No envy, no hard feelings.

As a good boss, Yavlinsky was out to promote his subordinates. One of my fellow workers, Edouard Kuznetsov, told me about the issue of a trip of the first CTF delegation to France. In those days there were no "exit commissions" that screened people on an individual basis-the buck stopped at Kurchatov's. Dr. Stepan Lukyanov was selected as a member of the delegation. Then one had to choose between two young men-Vladimir Mukhovatov ("our guy") and Sergei Fanchenko employed in another department and having a

record of trips abroad. The balance was tipped in favor of Fanchenko who knew as many as twelve European languages, yet another point to his score. Kurchatov pondered. "Well, you'd better send him to a linguistic congress," Yavlinsky countered speaking to Kurchatov. Everybody burst out laughing, and Mukhovatov was chosen in the end. Not a member of the Communist Party, not married. One would rather send married people abroad at that time.

Mukhovatov is a great expert in high-temperature plasma and controlled nuclear fusion, who had done a good deal for the International Thermonuclear Experimental Reactor (ITER)* now under construction at Cadarache, France. Years after, while on a business trip in Japan, he cabled a short message on the late Yavlinsky's 90th birth anniversary. Looking back, he spoke of relationships between his former boss and young research fellows during the CTF initial years. "Nathan Yavlinsky always backed you up, you were in the focus of his attention. He admired you and thought much of you-you were more upright and clever than you figured yourself to be. He saw and understood the overt and covert motives of your actions, and he did not censure you, but grieved if your deeds did not match your inches. This might explain how humankind made up God in the human image."

And this is how Dr. Ksenia Razumova outlined Jawlinski's credo. "The progress of your subordinates is far more useful than your own progress. Take good care of them and help before they ask for help, then they would work in peace and with abandon. Never hold back one if he wants to quit, there will be fewer leavers. 'Be a good director of your plant' (his phrase!), and never complain someone was working bad-above or at your side. First you should give bonuses to common workers and laboratory assistants, and last, to their superiors; no bonuses for your own self."

Those were his immutable, abiding rules. He was truly a model of human amiability and dedication to science.

* See: V. Glukhikh et al., "On the Brink of Thermonuclear Era", Science in Russia, No. 3, 2003; L. Golubchikov, "Tokamak-International Challenge", Science in Russia, No. 1, 2004.--Ed.