Thomas H. Stix, Plasma Physicist, Dies at 76

By JAMES GLANZ

r. Thomas H. Stix, whose elegant mastery of the literally infinite complexities of waves in electrified gases helped create a new field of science, died on Monday in Princeton. He was 76 and an emeritus professor of astrophysical sciences at Princeton University.

The cause was leukemia, his wife, Hazel Sherwin Stix, said.

Dr. Stix's working medium was plasma, also known as ionized or electrified gas, and he was as comfortable with its quirks as a champion surfer in the curl of a breaker. More than 99 percent of the visible universe, including the sun, the stars and the thin gases of space, exists in the form of plasma, which can shake and oscillate in an endless variety of modes — unlike ordinary air, with its simple sound waves, radio waves and the like.

In the 1950's, Dr. Stix joined what was then a secret project at Princeton to extract energy from laboratory plasmas using thermonuclear fusion, the same process that powers the sun and stars. Dr. Stix soon devised a technique that he called a magnetic beach for generating microwaves that would then "break," or dissipate, inside the plasma, heating it to the huge temperatures needed for fusion. The antenna he invented for that purpose is now called a Stix coil.

Working both in the laboratory and with theoretical calculations, he found many ways to put waves to work in fusion research in succeeding decades, and his 1962 book, "The Theory of Plasma Waves," codified the subject in mathematical form for the first time.

"He put it together so that the rest of us could understand it as a whole," said Dr. William M. Hooke, a physicist who is retired from Princeton Plasma Physics Laboratory, where Dr. Stix did much of his wave research.

At the laboratory, Dr. Stix, who was also active in a number of human rights causes involving scientists around the world, organized the nation's first graduate program in plasma physics, which has awarded some 200 doctorates to date.

As the honors for his achievements piled up, Dr. Stix continued to project his trademark effortlessness, never quite letting on how seriously he took it all. In 1980, when he accepted the Maxwell Prize, the highest honor in plasma physics, listeners expecting a solemn speech instead heard lengthy recordings from Jack Benny's old radio show while Dr. Stix chuckled at the podium. The only connection was Mr. Benny's wheezing automobile, a Maxwell.

Dr. Robert J. Goldston, an astrophysics professor at Princeton and director of the Plasma Physics Laboratory, described the Benny anecdote as typical of Dr. Stix, who "just enjoyed the science and just enjoyed the insights in a very relaxed and humorous way, at the same time knowing it was of the utmost importance."

Thomas Howard Stix was born in St. Louis on July 12, 1924, and grew up near Washington University there. His family owned a dry goods business, Rice-Stix Inc., that had been among the largest businesses in the city around the turn of the century and existed into the 1950's. The family home on Forsyth Boulevard was eventually donated to the university; it is now the Stix International House.

From 1943 to 1946 he was an Army radio technician, and served in the South Pacific during the war. Dr. Gregory W. Hammett, a physicist at the Princeton plasma laboratory, said Dr. Stix liked to quip that he had the only office above Gen. Douglas MacArthur's in Tokyo — as a radio operator on the roof of the building.

After receiving a bachelor's from the California Institute of Technology, Thomas Stix went to Princeton and studied cosmic rays. He received his doctorate in 1953 and was recruited by Dr. Lyman Spitzer, a Princeton astrophysicist, to join Project Matterhorn, as the American fusion effort was then called.

Following ideas developed by Dr. Spitzer, Dr. Stix built devices to contain plasma, called stellarators, and eventually succeeded in creating high temperatures using the magnetic beach. Dr. Stix used that work as a springboard to devising successively more sophisticated ideas for heating plasmas with waves, techniques that dominate the field today.

Later in his career he turned to more speculative work on the environment, exploring the possibility that the atmosphere could be cleansed of certain pollutants using powerful lasers. Characteristically, he played down the possible effect of the work but clearly enjoyed working in an undeveloped field again.

Dr. Stix is survived by his wife of 51 years; two brothers, Ernest W., a sculptor in St. Louis, and John, of Nyack, N.Y., a longtime member of the Juilliard faculty; a son, Dr. Michael S., of Lexington, Mass.; a daughter, Susan S. Fisher of New York City; and four grandchildren.

As profound as his impact on his field was, Dr. Stix kept his philosophy simple in discussions with the many students who turned to him for advice. When asked why he chose physics as a vocation, his answer was straightforward: "You get paid for your hobby."