PPPL honors physicists Steven Sabbagh and Gregory Hammett
PPPL presented its 2013 outstanding research awards to physicists Steven Sabbagh and Gregory Hammett following Director Stewart Prager’s May 28 State-of-the-Laboratory Address. Sabbagh received the Kaul Foundation Prize for Excellence in Plasma Physics Research and Technology Development for his work on advancing the understanding, and enhancing the stability, of high-performance plasmas in fusion facilities called tokamaks. Hammett was named winner of the Distinguished Research Fellow Award for his work on deepening the theoretical understanding of turbulence in fusion plasmas.
Sabbagh, a senior research scientist at Columbia University and an adjunct professor of applied physics at Columbia, was the first long-term collaborator at PPPL to receive the Kaul Prize, which includes a $6,000 cash award. Former PPPL Director Ronald Davidson endowed the prize by giving Princeton University a portion of the gift he received as the 1993 recipient of the Award for Excellence in Science, Education and Physics from the Kaul Foundation in Tampa, Florida.
The honor for Hammett, a principal research physicist at PPPL, includes a $5,000 cash award supported by the U.S. Department of Energy. The recognition is part of the Laboratory’s Distinguished Research and Engineering Fellow Program, which honors members of the PPPL scientific and engineering staffs for their accomplishments.
Sabbagh has worked as a research scientist and has led a group of Columbia University researchers conducting experiments at PPPL for more than two decades. He has mentored students doing research at the Laboratory as well. “We’re very pleased to make this award to Steve,” said Michael Zarnstorff, PPPL deputy director for research. “We deeply value his contributions to the Lab and to the U.S. fusion program through the facilities here, and to the role that he’s played as a leader of experimental programs.”
Sabbagh began work as a full-time, on-site collaborator at PPPL after earning his Ph.D. from Columbia in 1990. He first created plasmas on the Tokamak Fusion Test Reactor (TFTR) that significantly exceeded previous limits for a crucial factor called “beta”—the ratio of the pressure of the plasma to the strength of the magnetic field that confines it. The higher the beta, the more cost-effective the confinement. These high-beta plasmas produced some of the highest fusion power in the operation of TFTR.
Sabbagh next moved to the National Spherical Torus Experiment (NSTX), where he investigated ways to stabilize plasma at high beta by controlling phenomena called resistive wall mode instabilities. His research produced record betas that surpassed a stability milestone called the “no-wall limit” by as much as a factor of two. He plans to continue to advance such research when the NSTX upgrade is completed next year.
Sabbagh conducts complementary experiments on the KSTAR superconducting tokamak in South Korea and the DIII-D tokamak in San Diego, and has been awarded a number of honors. He received the Nuclear Fusion Award from the International Atomic Energy Agency in 2009 and was elected an American Physical Society Fellow in 2010. He lives in Warren with his wife, Mary Lepore-Sabbagh, who has worked in information technology for Bell Labs and Lucent Technologies.
Hammett specializes in computational and theoretical studies of the complex physics of plasma turbulence and has been a fellow of the American Physical Society since 1997. “Greg is a scholar known worldwide for his seminal contributions to plasma kinetic theory,” said Amitava Bhattacharjee, who heads the Theory Department at PPPL. “Along the way, he has mentored outstanding students who have gone on to make striking contributions to theoretical and computational plasma physics.”
Hammett first came to PPPL as a summer college student in 1979 and began his career at the Laboratory the following year, first as a graduate student and then as a member of the research staff, which he joined in 1986 after completing his Ph.D. He became increasingly interested in turbulence in fusion facilities in the late 1980s and has made that the focus of most of his career. He and collaborators seek to develop improved computer simulations of this turbulence, first to understand how future fusion devices will perform and then to find ways to improve their performance.
Hammett began teaching in the Princeton Program in Plasma in Physics in 1995 and has been a lecturer with the rank of professor since 2001. He has supervised nine Ph.D. students. He served as director of graduate studies for the program in spring, 2013, and is currently a visiting research fellow at Merton College at the University of Oxford. There he lives in a house that dates to the 1300s and once served as a meeting place for thinkers such as the philosopher John Locke and the scientist Robert Boyle. He will be returning to his home in Plainsboro, where he resides with his wife of 25 years, Kate.
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