A 1997 recipient of the National Medal of Science, the nation's highest scientific honor, for his many fundamental contributions to the field of nuclear fusion and plasma physics, Rosenbluth was known internationally for his leadership in developing nuclear fusion as a future energy source and for his wide-ranging contributions to national security.
"Marshall was a scientist of towering stature who was affectionately known as the 'Pope of Plasma Physics'," said Marvin L. Goldberger, an emeritus physics professor at UCSD, a former president of the California Institute of Technology and a former director of the Institute for Advanced Study in Princeton, N.J. "He was a marvelous human being, my friend and colleague for 57 years."
Rosenbluth's work spans the history of fusion research. Shortly after receiving his doctorate from the University of Chicago in 1949 at the age of 22, he began an analysis of the scattering of relativistic electrons within nuclei, which led to his discovery of the so-called Rosenbluth formula-a staple of college physics courses.
In 1950, Rosenbluth was recruited by Edward Teller as one of the principal theoreticians at the Los Alamos Scientific Laboratory in New Mexico, doing classified research that led to the development of the hydrogen bomb. Rosenbluth later joined a small group of eminent scientists that investigated the possible peaceful uses of nuclear energy. During this period, Rosenbluth led the research effort that developed the Monte Carlo algorithm, now a standard tool for research in statistical mechanics, chemistry, biochemistry and many other fields.
He was a senior research advisor at General Atomics in San Diego from 1956 to 1967, a professor of physics at UCSD from 1960 to 1967 and from 1987 to 1993, a professor at the Institute for Advanced Study from 1967 to 1980, director of the Institute for Fusion Studies at the University of Texas from 1980 to 1987, then returned to La Jolla, where he eventually retired in 1993 as a professor emeritus of physics at UCSD. Throughout his career, Rosenbluth maintained a close association with General Atomics and was active as a consultant there until shortly before his death.
He served as a key advisor to the Department of Energy for magnetic and inertial confinement fusion research and for a range of issues relating to national defense and disarmament. He was also a member of the prestigious National Academy of Sciences and received numerous awards over his career, including the E. O. Lawrence Prize, the Albert Einstein Award and the Enrico Fermi Award.
Rosenbluth is widely regarded by colleagues in the U.S. and abroad as a leader in fostering international collaboration in fusion and physics research. He was a central member of the International Center for Theoretical Physics in Trieste, Italy, and of the International Thermonuclear Reactor, a program to build a fusion reactor to demonstrate the feasibility of using fusion to generate power, which had its U.S. headquarters in San Diego.
At his 75th birthday celebration at UCSD, which drew more than a hundred eminent scientists from around world, Rosenbluth was honored for his "dedication to science, intellectual integrity, fairness, accessibility and his keen wit and sense of humor."
"He has trained and mentored an entire school of postdocs in theoretical plasma physics," Patrick H. Diamond, a professor of physics at UCSD and his close colleague said in his testimonial. "He has tirelessly worked to enhance international cooperation in science and in general. Of the many testimonials he's received in his honor, perhaps the most accurate summation of Marshall Rosenbluth the man is 'Marshall taught us that what was right was more important than who was right'."
Rosenbluth is survived by his wife Sara and his four children from a previous marriage, Alan Edward, Robin Ann, Mary Louise and Jean Pamela. His family requests that in lieu of flowers, donations be sent to the Marshall Rosenbluth Memorial Fund in the Division of Physical Sciences at UCSD.