Pyotr Leonidovich Kapitsa

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Pyotr Leonidovich Kapitsa

The Soviet physicist Pyotr Leonidovich Kapitsa (1894-1984) made notable contributions to knowledge of atomic structures and to understanding the behavior of matter in strong magnetic fields and at extremely low temperatures.

Pyotr Kapitsa was born on July 8, 1894, in Kronstadt near St. Petersburg (Leningrad) and was raised in Tsaritsyn (Volgorad). He obtained his education in the physical sciences and engineering at the high school of Kronstadt and at the Polytechnic Institute of Petrograd (St. Petersburg), from which he graduated in 1918. The following year he became a lecturer at the Polytechnic Institute. He published six papers between 1916 and 1921, which clearly reveal his wide-ranging interests and his skillful and ingenious experimentation.

On the recommendation of a colleague and the personal intercession of a well-known Russian writer, Kapitsa was able to leave the country in 1921 as a member of a scientific mission representing the Soviet Academy of Sciences. In July of that year Kapitsa met Ernest Rutherford, impressed him favorably, and was invited to work in the Cavendish Laboratory at Cambridge, England. Preferring to continue his studies of physics under Rutherford, Kapitsa temporarily suspended his activities with the scientific mission.

Cambridge Period

From 1921 until 1934 the Cavendish Laboratory was Kapitsa's home. The professional respect that Kapitsa and Rutherford initially displayed toward each other matured into an enduring and warm friendship. After a year's activity in the Cavendish Laboratory, Kapitsa was impressed with the English commitment to individualism in scientific research and to insistence of obtaining results; he believed that the Soviet physicists would benefit more by following the English pattern instead of the German model.

Kapitsa's early experiments in the Cavendish Laboratory were in nuclear physics. He constructed a microradiometer, an instrument capable of measuring the energy of the rays emitted by radium, and was able to determine the loss of energy of a beam of alpha particles as it passed through air and carbon dioxide gas. After 3 1/2 months of investigating alpha particles, Kapitsa was excited when he managed to produce the first photograph of three distorted tracks of alpha particles in a strong magnetic field.

Another area requiring Kapitsa's engineering ability was cryogenics. When he turned to low-temperature physics, the Royal Society Mond Laboratory was built for him and others interested in the pioneering areas of physics. The Mond Laboratory officially opened on Feb. 3, 1933, and Kapitsa was its first director. It was here that he constructed a helium liquefier capable of producing 2 liters of helium an hour; this cryogenic apparatus made possible experiments at extremely low temperatures.

Stalin's Captive Physicist

Kapitsa and his wife traveled to the Soviet Union (Russia) several times, but in the fall of 1934 their exit visas were unexpectedly canceled. The following year Kapitsa and Stalin came to a reconciliation resulting in Kapitsa's being appointed director of the Institute of Physical Problems, part of the U.S.S.R. Academy of Sciences, founded on Dec. 28, 1934; in negotiations for the acquisition of his equipment at the Mond Laboratory; and in reuniting Kapitsa and his wife with their two children.

The Institute of Physical Problems was purposely designed to enable Kapitsa to continue his work with strong magnetic fields and low temperatures. In 1937 he began a series of experiments with helium II, whose thermal conductivity is 3 million times greater than normal helium (helium I) and about a million times greater than copper. A consequence of his study was the discovery of the phenomenon of superfluidity, whereby atoms move among each other without friction. However, World War II interrupted his investigations; he returned to the field of nuclear physics, experimented with uranium, built instruments for the study of cosmic rays, and delivered scientific lectures before the command staff of the Red Army.

There was speculation in 1945-1946 that Kapitsa was working on the Soviet atomic bomb, but he consistently and vigorously denied this. Late in 1946 his name vanished from public view, and secrecy surrounded his work. He was under house arrest in Zvenigorod, a suburb of Moscow, from 1946 until the death of Stalin in 1953, for refusing to cooperate with Soviet authorities on projects to improve atomic military capability. During this period of restriction Kapitsa produced papers dealing with heat transfer, the problem of the wave flow of thin viscous fluid layers, the problem of determining the effect of airflow on a flowing liquid, and a study on the dynamic stability of a moving pendulum with a vibrating suspension. It is now becoming evident that Kapitsa and his collaborators had done some remarkable theoretical work in the area of high-power electronics between 1946 and 1955; the monographs in this field began to appear after 1961. For example, Kapitsa and his colleagues considered the possibility of constructing generators, such as the plane magnetron, for producing ultrahigh frequencies which could be used for the transmission of electrical energy in waveguides.

In 1978, Kapitsa received a share of the Nobel prize for his work in low temperature physics. He died in Moscow on April 8, 1984.

Outlook and Philosophy

In many respects Kapitsa was more British than Russian in his approach to science, believing that it should be free to question and probe, that it should be buttressed by experimentation, and that it should be unfettered by political ideologies. In the article "Theory, Experiment, Practice" (1962), Kapitsa castigated the divergence between Soviet theoretical and experimental physicists, the ignorant application of dialectical materialism to science by Marxist philosophers who know little about science, and the general divorcement between theory and practice in Soviet science. In another piece he insisted that science is an international enterprise and that international cooperation and contact are a necessity if science is to progress.

Respecting the future course of science, Kapitsa discussed in "The Future of Science" (1962) the tremendous challenge mankind faces in the conquest of outer space. He foresaw the use of nuclear energy to power space vehicles, the use of outer space for the disposal of dangerous radioactive waste products, and the easing of population pressure on earth through colonization of other planets. Turning to biology, Kapitsa believed that genetics can be extremely valuable if scientists can produce desired mutations.

Of special interest were Kapitsa's views on the social sciences. It was his opinion that the social sciences are at the same level of historical development that the natural sciences were during the Middle Ages, which in part explains the wide chasm between the natural and the social sciences; it is only with the emergence of the science of man's higher nervous activity that the social sciences have finally been provided with an empirical base. Being a man of peace, Kapitsa pleaded that the social sciences be developed intensively in order to create a social system of states that would make war impossible.