Mikhail Solomonovich Ioffe (; 2 September 191714 July 1996) was a

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

best known for his work on

magnetic mirror A magnetic mirror, also known as a magnetic trap or sometimes as a pyrotron, is a type of magnetic confinement fusion device used in fusion power to trap high temperature Plasma (physics), plasma using magnetic fields. The mirror was one of the e ...

fusion devices, and especially his 1961 experimental device that demonstrated gross plasma stability was possible in a properly arranged

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

. His concept is known today as "". Viewed with disfavour by the Soviet establishment for his cordial ties with his counterparts in the west, he was forbidden from leaving the Soviet Union until the

dissolution of the Soviet Union The Soviet Union was formally dissolved as a sovereign state and subject of international law on 26 December 1991 by Declaration No. 142-N of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. Declaration No. 142-Н of ...

. He subsequently received numerous international awards.

Life

Ioffe was born on 2 September 1917 in

Samara Samara, formerly known as Kuybyshev (1935–1991), is the largest city and administrative centre of Samara Oblast in Russia. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with a population of over 1.14 ...

. He studied

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

Leningrad University Saint Petersburg State University (SPBGU; ) is a public university, public research university in Saint Petersburg, Russia, and one of the oldest and most prestigious universities in Russia. Founded in 1724 by a decree of Peter the Great, the uni ...

and graduated in 1940 with a diploma, roughly similar to a

master's degree A master's degree (from Latin ) is a postgraduate academic degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional prac ...

. He served in the

Red Army The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Republic and, from 1922, the Soviet Union. The army was established in January 1918 by a decree of the Council of People ...

from 1941 to 1946. On leaving the Army, Ioffe became a staff member of the Physico-Technical Institute of Leningrad. In 1948 he moved to the

Kurchatov Institute The Kurchatov Institute (, National Research Centre "Kurchatov Institute") is Russia's leading research and development institution in the field of nuclear power, nuclear energy. It is named after Igor Kurchatov and is located at 1 Kurchatov Sq ...

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

, at that time known simply as "Laboratory No. 2", where he spent the rest of his working life. He gained his candidate's degree (PhD) in 1953 and Doctor of Science degree in 1971. His work was mostly concerned with the properties of plasma in the field of

nuclear fusion Nuclear fusion is a nuclear reaction, reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/neutrons, neutron by-products. The difference in mass between the reactants and products is manifested as either the rele ...

. In 1956 he was promoted to lead a small group studying the problem of micro-instabilities in plasma, a previously unknown issue that was causing significant problems in existing reactor designs. In particular, a type of

plasma instability In plasma physics, plasma stability concerns the stability properties of a plasma in equilibrium and its behavior under small perturbations. The stability of the system determines if the perturbations will grow, oscillate, or be damped out. It ...

known as the

flute instability The flute is a member of a family of musical instruments in the woodwind group. Like all woodwinds, flutes are aerophones, producing sound with a vibrating column of air. Flutes produce sound when the player's air flows across an opening. In th ...

was causing problems in the

design. Basic analysis carried out in both the Soviet Union and the US independently came to the same conclusion; any area where the magnetic field was convex with the plasma on the inside of the curve would cause the plasma to be ejected from the reactor. Ioffe's team came up with a new arrangement of fields for the mirror, today known as the "minimum-B" or "magnetic well" configuration. By adding additional magnets to the mirror, the internal fields were modified so that the plasma sat within an area that was convex everywhere. Ioffe led the construction of a device to test this theory, adding six current conducting bars to a conventional mirror to modify the internal field. Testing the performance was simple, with back-to-back tests running the bars with or without current; the former demonstrated a 35-fold improvement in confinement time. The results of this device were presented in 1961 at the Conference on Fusion Research in

Salzburg, Austria Salzburg is the fourth-largest city in Austria. In 2020 its population was 156,852. The city lies on the Salzach River, near the border with Germany and at the foot of the Alps mountains. The town occupies the site of the Roman settlement ...

, where they were the highlight of the show. The US mirror team also attended the show and presented data showing no sign of the instabilities even though they were not using the magnetic well configuration. This was something of a mystery until

Lev Artsimovich Lev Andreyevich Artsimovich ( Russian: Лев Андреевич Арцимович, February 25, 1909 – March 1, 1973), also transliterated Arzimowitsch, was a Soviet physicist known for his contributions to the Tokamak— a device that produ ...

asked a question about whether one of the key measurement devices had been calibrated to account for a well known delay in its output. The mystery was solved; accounting for this delay demonstrated that the US mirrors were completely unstable as Ioffe's work suggested. Mirrors were not the only target of Ioffe's work on instability, he also solved a longstanding mystery of anomalous transport (rapid leakage) in the magnetic cusp concept and developed significant theory on magneto-electrostatic confinement which led to the later tandem mirror concept. Throughout his career, Ioffe received many honours from the Soviet government. However, he was viewed with suspicion by the same government due to his cordial ties with his counterparts in the west. In 1969 he was forced to decline the

Atoms for Peace Award The Atoms for Peace Award was established in 1955 through a grant of $1,000,000 by the Ford Motor Company Fund. An independent nonprofit corporation was set up to administer the award for the development or application of peaceful nuclear technol ...

. He was only able to visit the US in 1993 to attend the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

's plasma physics meeting.

References

Bibliography

* * {{DEFAULTSORT:Ioffe, Mikhail 1917 births 1996 deaths Scientists from Samara, Russia Atoms for Peace Award recipients Full Members of the USSR Academy of Sciences Soviet nuclear physicists Recipients of the Stalin Prize Recipients of the USSR State Prize Recipients of the Order of the Red Star Soviet military personnel of World War II