Hannes Olof Gösta Alfvén (Swedish: [alˈveːn]; 30 May 1908 – 2 April 1995) was a Swedish electrical engineer, plasma physicist and winner of the 1970 Nobel Prize in Physics for his work on magnetohydrodynamics (MHD). He described the class of MHD waves now known as Alfvén waves. He was originally trained as an electrical power engineer and later moved to research and teaching in the fields of plasma physics and electrical engineering. Alfvén made many contributions to plasma physics, including theories describing the behavior of aurorae, the Van Allen radiation belts, the effect of magnetic storms on the Earth's magnetic field, the terrestrial magnetosphere, and the dynamics of plasmas in the Milky Way galaxy.
Alfvén received his PhD from the University of Uppsala in 1934. His thesis was titled "Investigations of High-frequency Electromagnetic Waves".
In 1934, Alfvén taught physics at both the University of Uppsala and the Nobel Institute for Physics (later renamed the Manne Siegbahn Institute of Physics) in Stockholm, Sweden. In 1940, he became professor of electromagnetic theory and electrical measurements at the Royal Institute of Technology in Stockholm. In 1945, he acquired the nonappointive position of Chair of Electronics. His title was changed to Chair of Plasma Physics in 1963. From 1954 to 1955, Alfvén was a Fulbright Scholar at the University of Maryland, College Park. In 1967, after leaving Sweden and spending time in the Soviet Union, he moved to the United States. Alfvén worked in the departments of electrical engineering at both the University of California, San Diego and the University of Southern California.
In 1991, Alfvén retired as professor of electrical engineering at the University of California, San Diego and professor of plasma physics at the Royal Institute of Technology in Stockholm.
Alfvén spent his later adult life alternating between California and Sweden. He died at the age of 86.
In 1937, Alfvén argued that if plasma pervaded the universe, it could then carry electric currents capable of generating a galactic magnetic field. After winning the Nobel Prize for his works in magnetohydrodynamics, he emphasized that:
In order to understand the phenomena in a certain plasma region, it is necessary to map not only the magnetic but also the electric field and the electric currents. Space is filled with a network of currents which transfer energy and momentum over large or very large distances. The currents often pinch to filamentary or surface currents. The latter are likely to give space, as also interstellar and intergalactic space, a cellular structure.
His theoretical work on field-aligned electric currents in the aurora (based on earlier work by Kristian Birkeland) was confirmed in 1967, these currents now being known as Birkeland currents.
British scientist Sydney Chapman was a strong critic of Alfvén. Many physicists regarded Alfvén as espousing unorthodox opinions R. H. Stuewer noting that "... he remained an embittered outsider, winning little respect from other scientists even after he received the Nobel Prize..." and was often forced to publish his papers in obscure journals. Alfvén recalled:
When I describe [plasma phenomena] according to this formalism most referees do not understand what I say and turn down my papers. With the referee system which rules US science today, this means that my papers are rarely accepted by the leading US journals.
Alfvén played a central role in the development of:
Solar phenomena investigation (such as the solar wind)
In 1939, Alfvén proposed the theory of magnetic storms and auroras and the theory of plasma dynamics in the Earth's magnetosphere. This was the paper rejected by the U.S. journal Terrestrial Magnetism and Atmospheric Electricity.
Applications of Alfvén's research in space science include:
Van Allen radiation belt theory
Reduction of the Earth's magnetic field during magnetic storms
Magnetosphere (protective plasma covering the Earth)
Dynamics of plasmas in the galaxy