picture of the day
Japan's Hinode solar telescope
observes Alfvén waves in the Sun's corona.
May 30, 2008
Hannes Alfvén: the Maverick Plasma
100 years ago today on May 30th, 1908,
Hannes Olof Gösta Alfvén was born in Norrköping, Sweden,
about 100 miles southwest of Stockholm.
Hannes Alfvén is considered one of the founding fathers in the field of plasma
physics. He described himself as a dissident scientist and maverick, and
attitudes towards him are ambivalent. On the one hand, he received the 1970
Nobel Prize in physics for applications of his work in different areas of plasma
physics. On the other hand, some of his contributions to science have been
either ignored, forgotten, or unacknowledged.
After obtaining degrees in theoretical and experimental physics and in
mathematics, Alfvén was awarded a doctorate for his thesis, “Investigations of
the Ultra-Short Electromagnetic Waves". He soon moved into electronics and
astronomy, however, after becoming interested in cosmic rays and in 1933 having
his paper published in the journal Nature. All of his subsequent work was
guided by the principle that all new theories must be consistent with
experimental results from the laboratory, since the laws of Nature must apply
In 1937 Alfvén suggested that interstellar galactic space was permeated by ions
(a plasma) and could also carry electric and magnetic fields. By 1942, Alfvén
had devised a theory regarding the origin of the Solar System from a cloud of
ionized gas, and he noted "electromagnetic forces have been more important than
Hannes Alfvén on a postage stamp
from the Republic of the Congo
Around this time, Alfvén revisited the work initiated by Kristian Birkeland on
the Earth's aurora. As a result he developed the guiding-center approximation,
a way to approximate the motion of a charged particle in a magnetic field. At
that time it was taking two weeks to make the calculations. He also developed
the concept of frozen-in magnetic field lines, which is widely used today
but which Alfvén later warned can be highly misleading.
This work led to Alfvén's basic formulation of plasma physics,
magnetohydrodynamics, which is the study of electrically conducting fluid
dynamics. Alfvén first predicted that waves could occur in plasmas in a letter
in Nature in 1942, but it was largely ignored or disputed on the grounds that if
such waves existed, Maxwell would have noted them. Then in 1949, Alfvén gave a
lecture in Chicago that Enrico Fermi also attended. Fermi’s reputation was such
that when he nodded in agreement with Alfvén's presentation, the next day the
world acknowledged that such waves existed.
Alfvén also predicted (with Nicolai Herlofson) cosmic synchrotron radiation,
which is characteristic of electrons moving in magnetic fields. He also proposed
a mechanism by which a moving gas can be ionized when it reaches a certain
speed, called the critical ionization velocity. He also predicted the
existence of rings around Uranus.
Alfvén earned a number of accolades, including the Gold Medal of the Royal
Astronomical Society (1967), the Nobel Prize in physics (1970), the Gold Medal
of the Franklin Institute (1971), and the Lomonosov Medal of the USSR Academy of
Sciences (1971). In his name was created the Hannes Alfvén Medal. He also
created the Alpha-Centauri medal, to be given to the first person who is able to
prove whether the star Alpha Centauri is made of either normal matter or
Alfvén was married to Kerstin Erikson (1910-1992), and they had five children
together. He died in 1995 at the age of 86.
Hannes Alfvén biographical memoirs:
(Proceedings of the American Philosophical Society, Vol.
150, No. 4, 2005.)
Gosta Alfven. 30 May 1908-2 April 1995", R. S. Pease; S.
Lindqvist, in Biographical Memoirs of Fellows of the Royal
Society, Vol. 44, Nov. 1998 (Nov., 1998), pp. 2-19.
(1908 - 1995), Alfvén Laboratory, Sweden.
Hannes Alfvén bibliography:
Contributed by Ian Tresman
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