Kapitsa, Petr

Born June 26 (July 8), 1894, in Kronstadt. Soviet physicist; academician (1939; corresponding member from 1929) and member of the Presidium of the Academy of Sciences of the USSR (since 1957). Hero of Socialist Labor (1945). Son of a military engineer.

Kapitsa worked at the Petrograd Polytechnic Institute after his graduation (1918). In 1921 he was sent on a scientific trip to Great Britain, where he conducted research under the supervision of E. Rutherford. From 1924 to 1932 he was deputy director of the Cavendish Laboratory and, from 1930 to 1934, director of the Mond Laboratory in Cambridge. From 1935 to 1946 and since 1955 he has been director of the Institute of Physical Problems of the Academy of Sciences of the USSR, which he founded. He has been a professor at the Moscow Physicotechnical Institute since 1947. In 1920, working with N. N. Semenov, he proposed a method for determining the magnetic moments of atoms in an atomic beam. In 1923 he was the first to place a cloud chamber in a strong magnetic field and to observe the tracks of alpha particles.

In 1924, Kapitsa proposed the pulse method of generating superstrong magnetic fields and developed a device in which fields of up to 320 kilogauss were produced. In 1928 he observed the linear dependence of the electric resistance of a number of metals on the field intensity in strong magnetic fields (Kapitsa’s law). In 1934 he developed a device for liquefying helium by the adiabatic method, in which a piston-driven gas-expansion machine operated with a gaseous lubricant. In 1939 he presented a new method of liquefying air by using a low-pressure cycle accomplished in a high-efficiency expansion turbine (State Prize of the USSR, 1941), which is used widely to produce gaseous and liquid oxygen in large quantities.

In 1938, Kapitsa discovered the superfluidity of liquid helium (State prize of the USSR, 1943) and showed that on transfer of heat from a solid (such as the walls of a vessel) to liquid helium, a temperature jump (Kapitsa’s temperature jump) occurs at the interface. In 1947 he conducted studies of wave and thermal processes in moving thin layers of fluid and developed the quantitative theory of the interaction of sea waves with the wind. In 1955 he presented a hydrodynamic theory of lubricated rolling and suggested the idea that ball lightning is by nature a stationary superhigh-frequency discharge in the atmosphere. In 1950–55 he developed new types of superhigh-frequency generators, the planotron and the nigotron, with a power of up to 300 kilowatts in the continuous mode, and observed that during high-frequency discharge in dense gases a stable plasma column in which the electron temperature is assumed to be 10⁵—10⁶ °K is formed. This work, published in 1969, opened up a new direction for research in controlled thermonuclear fusion.

Since 1955, Kapitsa has been editor in chief of Zhurnal ek-sperimentaVnoi i teoreticheskoi fiziki (Journal of Experimental and Theoretical Physics). He is a member of the Soviet National Committee of the Pugwash Conference. He is a member of the London Royal Society (1929), The National Academy of Sciences of the United States (1946), the Danish Royal Academy of Sciences (1946), the Swedish Royal Academy of Sciences (1966), the Polish Academy of Sciences (1963), and many other foreign academies and scientific societies. Kapitsa has received five orders of Lenin, the Order of the Red Banner of Labor, and medals.