Robert Kraichnan

Born on 15 January 1928 in Philadelphia, Robert Kraichnan was a theoretical physicist and pioneer in modern turbulence theory. Kraichnan received his PhD from MIT in 1949. From 1949 to 1950, he served as an assistant to Albert Einstein at the Institute for Advanced Study in Princeton, New Jersey. Kraichnan then worked at Columbia University and the Courant Institute of Mathematical Sciences at New York University before leaving academia in 1962 to set up his own scientific consulting business, first in New Hampshire and later in New Mexico. Funded by government grants, Kraichnan consulted for such agencies as Los Alamos National Laboratory, NASA, the National Center for Atmospheric Research, the Naval Research Laboratory, and Woods Hole Oceanographic Institution. Over his career, Kraichnan worked in a number of fields, including general relativity, quantum field theory, quantum many-body theory, and statistical physics. His seminal work concerned turbulence and fluid mechanics. One of his most significant discoveries was that two-dimensional turbulence exhibits an inverse energy cascade, in which eddies actually increase in size rather than decrease. That finding proved important for studies of the oceans and the atmosphere, whose layered structures more closely approximate a two-dimensional, rather than three-dimensional, model. Among the awards Kraichnan received were the 2003 Dirac Medal from the Abdus Salam International Centre for Theoretical Physics and the American Physical Society’s 1993 Otto Laporte Award and 1997 Lars Onsager Prize. In 2000 he became a member of the National Academy of Sciences. Kraichnan returned to academia in 2003, joining the faculty of Johns Hopkins University as a professor of mechanical engineering, a position he held until his death in 2008. (Photo credit: Judy Kraichnan, courtesy AIP Emilio Segrè Visual Archives, Physics Today Collection)

Date in History: 15 January 1928