Professor John W. Belcher

Telephone: (617) 253-4285
Fax: (617) 253-0861
email: jbelcher@mit.edu

I am Class of 1922 Professor of Physics in the Astrophysics Division of the MIT Department of Physics at MIT. I am also a MacVicar Faculty Fellow, and have been heavily involved in the effort to change introductory physics at MIT to an interactive format (and I have the scars to prove it, see my MIT Faculty News Letter article).

My research interests are space plasma physics, outer planet magnetospheres, solar wind in the outer heliosphere, and astrophysical plasmas. I was Principal Investigator on the Voyager Plasma Science Experiment during the Voyager Nepture Encounter--the end of the Grand Tour. I am now a Co-Investigator on the Plasma Science Experiment onboard the Voyager Interstellar Mission.

I have twice received the NASA Exceptional Scientific Achievement Medal, once for my contributions to the understanding of the plasma dynamics of the Jovian magnetosphere, in 1980, and once for my role as Principal Investigator on the Plasma Science Experiment on Voyager during the Neptune encounter, in 1990.

I was born in Louisiana in 1943, and graduated from Odessa High School in West Texas in 1961. I attended Rice University in Houston, graduating with a double major in math and physics in 1965, summa cum laude.

I then went to Caltech for graduate school. Feynman got the Nobel Prize the first year I was there, and later on, in 1969, Gell-Mann got one as well.

I did my doctoral thesis working with Professor Leverett Davis, Jr., who was an astrophysical theorist who had started off working on the galactic magnetic field. Early on in his career, he came up with an explanation for the observed polarization of starlight.

Davis' first graduate student was Eugene Parker, who originated the idea of the solar wind, the continuous expansion of the outer atmosphere of the sun at supersonic speeds. Davis was the first to suggest that the interstellar medium near the sun was blown away by the solar wind, with the result that the sun sits in a cavity in the interstellar medium about 100 AU (1 light day) in radius. Inside that cavity, the material is just the supersonically expanding outer atmosphere of the sun; outside that cavity, the material is the interstellar medium. Davis named this cavity the heliosphere.

Davis subsequently became involved in early space missions which measured the interplanetary magnetic field. For my thesis, I did some analysis of the data from one of those missions, Mariner 5, a 1967 mission to Venus, and also some theoretical work on the acceleration of the solar wind.

I came to MIT after my doctorate (1971), to work with Professors Herbert Bridge and Alan Lazarus, who had the plasma probe on board Mariner 5. Just after I came, the Space Plasma Group wrote a proposal for the Voyager mission to Jupiter and Saturn. After reaching these two planets as well as Uranus and Neptune, Voyager is still going strong. In its most recent incarnation, it is refered to as the Voyager Interstellar Mission. Within the next twenty years, it is probable that the MIT plasma instrument on Voyager 2 will make measurements in the interstellar medium.

The Voyager spacecraft never return to the sun. They reach the nearest star in about 30,000 years. Voyager 2 is headed toward Galactic Center.

Selected Publications:

Belcher, J.W. and L. Davis, Jr.: Large Amplitude Alfven Waves in the Interplanetary Medium, 2, J. Geophys. Res. 76, 3534, 1971.

Belcher, J.W.: Alfven wave pressures and the solar wind, Astrophys. J. 168, 509, 1971.

Belcher, J.W. and K.B. MacGregor: Magnetic Acceleration of Winds from Solar-type Stars, Astrophys. J. 210, 498-507, 1976.

Belcher, J. W., C. K. Goertz, J. D. Sullivan, M. H. Acuna: Plasma Observations of the Alfven Wave Generated by Io, J.Geophys. Res. 86, 8319, 1981.

Belcher, J.W., The Low Energy Plasma in the Jovian Magnetosphere, Physics of the Jovian Magnetosphere, ed. A. J. Dessler, Cambridge University Press, 1983.

Belcher, John W., The Jupiter-Io Connection: An Alfven Engine in Space, Science 258, 133-248, 1987.

Belcher, J. W., H. S. Bridge, F. Bagenal, B. Coppi, O. Divers, A. Eviatar, G. S. Gordon, Jr., A. J. Lazarus, R. L. McNutt, Jr., K. W. Ogilvie, J. D. Richardson, G. L. Siscoe, E. C. Sittler, Jr., J. T. Steinberg, J. D. Sullivan, A. Szabo, L. Villanueva, V. M. Vasyliunas, and M. Zhang, Plasma Observations Near Neptune: Initial Results from Voyager 2, Science, 246, 1478-1483, 1989.

Belcher, John W., Alan J. Lazarus, Ralph L. McNutt, Jr. and George S. Gordon, Jr., Solar Wind Conditions in the Outer Heliosphere and the Distance to the Termination Shock, J. Geophys. Res. 15,177-15,183, 1993.


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