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Alfvén (Alfven), Hannes

( Swedish physicist. Nobel Prize in Physics, 1970)

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Biography Alfvén (Alfven), Hannes
genus. May 30, 1908
Swedish physicist Hannes Olof Gösta Alfvén was born in Norrköping in the family of Johannes and Anna-Clara (nee Romanus) Alfvén. Both his parents were practicing physicians. After graduating from high school in Norrköping, A. in 1926. enrolled in the University of Uppsala, in 1934. received his doctorate, and remained at the university where he lectured in physics until 1937, when he began to conduct research in physics at the Nobel Institute for Physics in Stockholm. A. assumed the post of professor in the theory of electricity at the Royal Institute of Technology in Stockholm in 1940, professor of electronics - in 1945 and professor in the field of plasma physics - in 1963. Four years later, he left Sweden in part because of their differences with the government on several issues - from education policy to develop a nuclear reactor - and was appointed professor at the University of California, Mr.. San Diego.
Earlier studies of A. to the nature of sunspots and auroras. Since the temperature of the sun is very high, . it consists of a special form of matter, . called plasma, . which is a gaseous mixture of electrons, . detached from the atoms and molecules with their high-energy collisions, . and ions, . also arisen as a result of such collisions,
. The stars and most of the matter in the universe consists of plasma, the plasma and the solar wind is a stream of particles emitted by the Sun. When these particles enter the Earth's magnetic field, they are deflected to the poles, and the collision with the ionosphere form auroras. A. made a lot of prophetic discoveries in physics of plasma, which appeared unexpectedly, and even rejected in his time. So, . example, . He showed, . that the plasma there is a magnetic field, . related to the flows of charged particles in it (electric currents), . and that, under certain conditions, this magnetic field may be 'frozen' in the plasma (if such a plasma moves, . then the field is moving along with it),
. In order for such conditions formed, . electrical conductivity in combination with other characteristics should be high enough, . and the particles should be located close enough to each other, . so that the similarity of collisions with neighbors to prevent the loss of electrons.,
. Considering the complicated motion of a charged particle in a magnetic field, A
. introduced a simplified approximation, . in which this movement is considered as a rapid rotation of particles around the 'guiding center', . which itself moves along the magnetic lines (magnetic field lines show the direction of the field at each point, the proximity of lines to each other reflects the magnitude of the field).,
. He applied this principle in the study of magnetic storms and auroras, finding that the particles in the Earth's magnetic field to drift along magnetic field lines, reflected from regions with high magnetic field strength
. The concept of magnetic scribbling proved very useful in work on controlled thermonuclear fusion, where there is a need to isolate the burning plasma, a contact which would have destroyed the walls of any vessel. Eden A., . though not necessarily shared by other scientists, . have proved fruitful in the interpretation of such phenomena, . as, . example, . radiation belt Van Allen (goroobraznye streams of electrons, . circulating in the Earth's magnetic field) or a decrease in the Earth's magnetic field during magnetic storms,
. Another of the early assumptions A., substantiated later, was the existence of large-scale weak magnetic fields in the galaxy because of the presence of even a small amount of plasma fields, which affect the motion of cosmic rays.
In 1942, Mr.. A. predicted that the magnetic lines in a plasma behave like a stretched rubber and can transmit perturbations, in many respects similar to those that occur when a pinch of violin strings, calling this phenomenon magnetohydrodynamic waves. This idea is contrary to prevailing notions, according to which electromagnetic waves can not penetrate deeply into an electrical conductor. Indeed, the use of sheet metal in order to avoid such penetration, it was commonplace. Although the theory of A., it seemed, could not find experimental confirmation, she began to gain recognition and was supported by Enrico Fermi, who listened to a lecture by. University of Chicago in 1948. Contrary to general expectations, these waves, which became known as Alfven waves, were found in a liquid metal in 1949 and in plasma in 1959
. Alfven waves have helped to explain the small changes in the Earth's magnetic field and the close relationship between magnetic disturbances that are separated by large distances, but related geomagnetic lines.
. In 1942, Mr.
. A. also showed both in terms of the evolution of the solar system from the plasma state due to a Goth fact that almost all of its momentum (the product of mass and velocity) falls on the planets, not the Sun. Many of the ideas A. appeared in the study of sunspots, and he came to the conclusion that they represent areas of intense magnetic fields embedded in the mass of the Sun. In 1943, considering the relationship between the plasma and its magnetic field, he explained why the sunspots, which is colder (and, consequently, have greater density) of their surroundings, because it is darker, not drowning. The reason is the magnetic pressure that counteracts the gravitational force.
. New area of physics, . known as magnetohydrodynamics, . which laid the foundations of A., . was important not only for research on nuclear fusion, . but also for development on such topics, . as supersonic flight, . rocket propulsion and braking of the landing of spacecraft, . And although most,
. primarily interested in the behavior of plasma in stars and in interplanetary and interstellar space. Collection of his early works 'Cosmic Electrodynamics' ( 'Cosmical Electrodynamics', 1950) has had an enormous impact on the specialists in astrophysics and plasma physics. More recent important work A. devoted to the formation of the solar system.
The belated recognition came to him, when A. received in 1970. Nobel Prize in Physics "for fundamental work and discoveries in magnetohydrodynamics and their fruitful applications in different fields of plasma physics'. He shared the prize with Louis Neel, awarded for their contribution to the theory of magnetism. When presenting the laureate Torsten Gustafsson, a member of the Royal Swedish Academy of Sciences, said in his speech that the idea of a. 'have found wide application in the field of astrophysics, especially in the study of the development phases of the solar system, formed when the planets and moons'. In his Nobel lecture A. said, . clarify that, . as the solar system, . - 'Is in fact one of the fundamental problems of science', . adding, . that from a philosophical point of view 'is an equally important question, . as the question of the structure of matter, . which attracted the most attention during the first two-thirds of our century '.,
. Taking care of that theory is firmly based on physical observations, A
. long fought for the use of satellites for scientific research. Specifically, . he advocated that, . that the spacecraft were sent mainly to asteroids and comets, . rather than on their natural satellites, . Believing, . that large bodies of information about the initial conditions almost completely lost due to internal mixing and surface erosion.,
. Formerly a supporter of nuclear power, A
. later became a warning of the dangers posed by nuclear plants. Worried about nuclear arms race, he began to take an active part in the Pugwash movement of scientists.
A. married Kerstin Maria Erikson in 1935, they have five children. In scientific papers, they are written non-fiction books, some of them co-authored with his wife. In his book 'Worlds - Antiworlds: antimatter in cosmology' ( 'Worlds-Antiworlds: Antimatter in Cosmology', . 1965) has been suggested, . the universe, . perhaps, . consists of equal quantities of matter and antimatter, . assumption, . contrary to many modern theories,
. Under the pseudonym Olof Iohannesson he wrote a science fiction novel 'The Great Computer: Foresight' ( 'The Great Computer: A Vision', . 1968), . describing, . as increasingly complex computers have gained control over the government initially, . and then over the entire globe.,
. First astrophysicist, Nobel Prize laureate, A
. was also awarded the gold medal of the Royal Astronomical Society in London (1967) and Gold Medal Lomonosov USSR (1971). He is a member of the Royal Swedish Academy of Sciences, Royal Society of London, other academies.

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Alfvén (Alfven), Hannes, photo, biography
Alfvén (Alfven), Hannes, photo, biography Alfvén (Alfven), Hannes  Swedish physicist. Nobel Prize in Physics, 1970, photo, biography
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