Prof. Eugene Newman Parker
Study of the Sun and its relation to the phenomena on Earth has been one of the central themes of modern scientific research. Professor Eugene Parker in undoubtedly one of the greatest living exponents of the science that has contributed deeply to our current knowledge and understanding of solar-terrestrial relations. He has carried forward the legacy of such pioneers as S. Chapman, W.M. Elsasser and Hannes Alfven and has profoundly influenced developments in astrophysics.
Eugene Newman Parker was born in Houghton, Michigan on June 10, 1927 exactly two months before the birth of the man in whose memory the current lecture series has been institutd. He received a B.S degree from Michigan State University in 1948 and a Ph.D from California Institute of Technology in 1951. From Caltech, Parker went to the University of Utah where he held various academic positions till 1955. During 1953-55, Parker worked with Elsasser and developed his love for cosmic magentic fields, which has been the recurring theme of much of his research. In 1955, Parker moved to the University of Chicago becoming a faculty member in the department of Physics in 1957 and in the department of Astronomy and Astrophysics in 1967. He retired in 1995 as the S. Chandrashekar Distinguished Service Professor at the Enrico Fermi Institute and the department of physics and astronomy of University of Chicago.
In 1957, Chapman had developed a static model of the outer atmosphere of the Sun, where he showed that owing to the high thermal conductivity of the corona, its temperature would remain high even at large distances from the Sun and the limiting pressure would be several orders of magniture higher than the value known to apply to the normal interstellar medium. Parker abandoned Chapman's static model in favour of a dynamic one with a steady outflow of material from th corona. He produced an elegant theory based on non-linear equations for observation of mass, momentum and energy and obtained different types of solutions. He developed solutions where the expansion speed increased with distance from the Sun reaching supersonic values of a few hundred kilometres per second and for which the pressure vanished in the limit of large distances, thus bringing consistency with the known interstellar values. Thus was born the theory of the solar wind, the central component of heliophysical phnomena which affect the climate on Earth in a variety of ways. Despite the elegance of Parker's mathematical description of the solar wind, his theory was not easily accepted by physicists of the time and his paper model needed editorial intervention to achieve publication in the Astrophysical Journal in 1958. The first direct observations of the solar wind, which came soon after its publication amply vindicated his theory.
Parker also studied the dynamic properties of the gaseous disc of our Galaxy, which is inflated by the magnetic field and cosmic rays, and demonstrated the basic barometric equilibrium of such a system. In his Henry Norris Russell Lecture to the American Astrnonomical Society in 1969, Parker spoke on the Origin of Magnetic Fields. Astronomers in nearly every specialized field can find areas where Parker has made significant contribution. In one of his recent popular articles (Physics Today, June 2000) entitled The Physics of the Sun and the Galaxy to Stars, Parker prefaced it with the remark,
"The Sun is stranger than you think, displaying mysterious
manifestations of familiar laws of Physics and posing new
problems with every major advance in exploratory measurement."
Parker's own research spanning more then four decades, has done much to motivate these exploratory measurements and has provided the correct scientific interpretation of such measurements.
Parker has been the recipient of the John Adam Fleming Medal and the William Bowie Medal of the American Geophysical Union in 1968 and 1990 respectively. He was awarded the George Ellery Hale Prize of the AAS Solar Physics Division in 1978, the Chapman Medal and the Gold Medal of the Royal Astronomical Society in 1980 and 1992 respectively, the Catherine Wolfe Bruce Medal of Astronomical Society of the Pacific in 1997, and the American Physical Society's James Clerk Maxwell Prize for Plasma Physics in 2003. Furthermore in 2003, he won the Inamori Foundation's Kyoto Prize for Basic Sciences. He has authored several books, perhaps the most well known among them is Cosmical Magnetic Fields published by the Oxford University Press in 1979.