Hannes Alfvén

Hannes Olof Gösta Alfvén (b. May 30, 1908; Norrköping, Sweden – d. April 2, 1995; Djursholm, Sweden) was a Swedish scientist who is considered one of the founding father of the field of space plasma physics.^[2] He made many contributions and discoveries associated with both terrestrial and cosmic plasmas, (not always acknowledged by his peers), and in 1970 he won the Nobel Prize in Physics for his work developing a theory of plasmas called magnetohydrodynamics.

He originally trained as an electrical power engineer and later moved to research and teaching in the fields of plasma physics. Alfvén’s contributions to plasma physics includes theories describing the behavior of aurorae, the Van Allen radiation belts, the effect of magnetic storms on the Earth’s magnetic field, magnetic and electric fields in cosmic plasmas, the terrestrial magnetosphere, and the dynamics of plasmas in our galaxy.

Introduction

In 1937 Alfvén argued that if plasma pervaded the universe, it could then carry electric currents capable of generating a galactic magnetic field^[3]. 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”^[4]

In 1974, his theoretical work on field-aligned electric currents in the aurora (based on earlier work by Kristian Birkeland) was confirmed by satellite observations, resulting in the discovery of Birkeland currents.

Education

Alfvén received his PhD from the University of Uppsala in 1934. His thesis was titled “Investigations of the Ultra-short Electromagnetic Waves.”

Early years

In 1934, Alfvén taught physics at both the University of Uppsala and the Nobel Institute for 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 non-appointive position of Chair of Electronics. His title was changed to Chair of Plasma Physics in 1963. 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.

Alfvén considered himself an electrical engineer foremost. During his scientific career, prior to winning the Nobel Prize, Alfvén was not generally recognized as a leading innovator in the scientific community (though they were using his work). He enjoyed the assertion that he was guilty of a fault or offence by the entry into areas not previously explored in astrophysics leveled by other cosmologists and theoreticians.

Contributions

Hannes Alfvén (1908-1995), winning the Nobel Prizing for his work on magnetohydrodynamics [1].

Alfvén’s work was disputed for many years by the senior scientist in space physics, the British-American geophysicist Sydney Chapman. Alfvén’s disagreements with Chapman stemmed in large part from trouble with the peer review system. Alfvén rarely benefited from the acceptance generally afforded senior scientists in scientific journals. He once submitted a paper on the theory of magnetic storms and auroras to the American journal Terrestrial Magnetism and Atmospheric Electricity, and his paper was rejected on the ground that it did not agree with the theoretical calculations of conventional physics of the time. He was regarded as a person with unorthodox opinions in the field by many physicists, ^[5], Stephen G. Brush notes that “.. he remained an embittered outsider, winning little respect from other scientists even after he received the Nobel Prize..”^[6], and often forced to publish his papers in obscure journals; Alfvén recalls:

“When I describe the plasma phenomena according to this formulism 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.”^[7]

He was awarded the Nobel Prize in Physics in 1970 for his work with magnetohydrodynamics (MHD). In 1988, Alfvén was awarded the Bowie medal by the American Geophysical Union for his work on comets and plasmas in the solar system.

Alfvén was one of the few scientists who was a foreign member of both the U.S. and Soviet Academies of Sciences.

Research

Alfvén played a central role in the development of:

Plasma physics

Charged particle beams

Interplanetary physics

Magnetospheric physics

Magnetohydrodynamics

Solar phenomena: investigation (such as the solar wind)

Aurorae science

In 1939, Alfvén proposed the theory of magnetic storms and auroras and the theory of plasma dynamics in the earth’s magnetosphere.

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)

Formation of comet tails

Formation of the solar system

Dynamics of plasmas in the galaxy

Fundamental nature of the universe

Alfvén’s views followed those of the founder of magnetospheric physics, Kristian Birkeland. At the end of the nineteenth century, Birkeland proposed (backed by extensive data) that electric currents flowing down along the earth’s magnetic fields into the atmosphere caused the aurora and polar magnetic disturbances.

Areas of technology benefiting from Alfvén’s contributions include:

Particle beam accelerators

Controlled thermonuclear fusion

Hypersonic flight

Rocket propulsion

Reentry braking of space vehicles

Contributions to astrophysics:

Galactic magnetic field (1937)

Identified nonthermal synchrotron radiation from astronomical sources (1950)

Alfvén waves (low frequency hydromagnetic plasma oscillations) are named in his honor. Many of his theories about the solar system were verified as late as the 1980s through external measurements of cometary and planetary magnetospheres. But Alfvén himself noted that astrophysical textbooks poorly represented known plasma phenomena:

“A study of how a number of the most used textbooks in astrophysics treat important concepts such as double layers, critical velocity, pinch effects, and circuits is made. It is found that students using these textbooks remain essentially ignorant of even the existence of these concepts, despite the fact that some of them have been well known for half a century (e.g, double layers, Langmuir, 1929; pinch effect, Bennet, 1934)”^[8]

Alfvén reported that of 17 of the most used textbooks on astrophysics, none mention the pinch effect, none mentioned critical ionization velocity, only two mention circuits, and three mentioned double layers.

Alfvén’s cosmologies

Alfvén and colleagues proposed an alternative cosmological theory, and with Oscar Klein, the Alfvén-Klein model, to both the Steady State and the Big Bang cosmologies. Alfvén believed the problem with the Big Bang was that astrophysicists tried to extrapolate the origin of the universe from mathematical theories developed on the blackboard. The Big Bang was a myth devised to explain creation, according to Alfvén.^[9]

Later years

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 adult life alternating between California and Sweden. He died at the age of 86.

Asteroid 1778 Alfvén is named in his honour, as is the Hannes Alfvén Medal “.. awarded for outstanding scientific contributions towards the understanding of plasma processes in the solar system and other cosmical plasma environments”.^[10]

Personal life

Alfvén had a good sense of humor and he participated in a variety of social issues and worldwide disarmament movements. He had a long-standing distrust of computers. Alfvén studied the history of science and oriental philosophy and religion. He spoke Swedish, English, German, French, and Russian, and some Spanish and Chinese.

Alfvén was married for 67 years to his wife Kirsten. They raised five children, one boy and four girls. His son became a physician, while one daughter became a writer and another a lawyer in Sweden.

Reference

Bibliography

For articles and papers, see Hannes Alfvén bibliography

Biographical information

Footnotes

External links

Online bibliography

• Hannes Alfvén bibliography