Princeton Plasma Physics Laboratory: Physicists Hong Qin and Ahmed Diallo recognized for outstanding research

Hong Qin and Ahmed Diallo, physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), received the Lab’s outstanding research awards for 2020 for their work in plasma physics to push forward advancements in fusion energy.

Qin received the Kaul Foundation Prize for Excellence in Plasma Physics Research and Technology Development for the recent development of structure-preserving algorithms for plasma physics. Diallo was named PPPL Distinguished Research Fellow for his groundbreaking studies of tokamak edge plasma dynamics and his development and utilization of novel plasma diagnostics. Each prize includes a $7,500 cash award. Steve Cowley, Laboratory director, presented the awards in a ceremony Dec. 18.

Qin (pronounced chin), a principal research physicist at PPPL since 2007, has been a distinguished theoretician and instructor of doctoral students in the laboratory and abroad. Endowing the Kaul Foundation Prize was former PPPL Director Ronald Davidson, who donated to 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.

Staff Research Physicist Diallo heads a research group at PPPL and previously won a DOE Early Career Award to study control of the volatile edge of the superhot plasma that fuels fusion reactions. The Distinguished Research Fellow honor is part of the Laboratory’s Distinguished Research and Engineering Fellow Program, which honors members of the PPPL scientific and engineering staffs for their achievements.

Hong Qin

Qin has managed a remarkably varied career. He conducts ground-breaking theoretical research while serving as a lecturer with the rank of professor in the Princeton University Department of Astrophysical Sciences. He shuttled between PPPL and positions as executive dean of the School of Nuclear Science and Technology at the University of Science and Technology of China from 2014 to 2017 and as director of the Theory Center for Magnetic Fusion in the Chinese Academy of Sciences from 2010 to 2018. He now focuses on designing algorithms for computer simulations that preserve fundamental properties of fusion plasmas and thus predict their dynamical behavior with improved accuracy.

“Hong and collaborators have recently developed novel structure-preserving algorithms
applicable to fully kinetic treatments of tokamak plasmas,” said Jon Menard, PPPL deputy director for research. “It will be very interesting to see if such capabilities can be extended to transport or global stability problems relevant to present experiments and future burning plasmas.”

Early career awards

Qin’s interest in plasma physics grew from his work as an undergraduate student at Peking University. He earned bachelor’s and master’s degrees in space physics from the university and in 1993 became a doctoral student in Princeton University’s Department of Astrophysical Sciences before joining PPPL in 1998. He initially worked with former Director Davidson, with whom he co-authored the book, “An Introduction to the Physics of Intense Charged Particle Beams in High Energy Accelerators,” and has since received DOE and U.S. Presidential early career awards and been elected an American Physical Society Fellow.

Qin teaches the first-year graduate course in plasma physics with Nat Fisch, director of the Program in Plasma Physics, whom he views as a mentor. “I took this course from Nat as a first-year student and am really a product of that program,” he said, adding, “I’m very thankful for this award. I’ve been here 27 years and I greatly enjoy and benefit from the excellent research environment at PPPL.”

Fisch noted how much he has appreciated co-teaching with Hong. “Because of his key contributions to essentially all its concepts and methods, Hong Qin is internationally recognized as shaping the emerging field of structure-preserving algorithms for plasma physics,” Fisch said. “The contours of this fascinating field are now essentially defined by his more than 40 recent publications. When he discusses this complex subject, he demonstrates his charming flair for intellectual history and context, showing connections between his own research and myriad sources both within and without the plasma literature, in the delightful and didactic style that also characterizes his classroom lectures. His being awarded the Kaul Prize for this work in the subject is so very appropriate.”

Ahmed Diallo

Ahmed Diallo’s research into developing and implementing tools, such as laser-based diagnostics, to understand the super-hot edge of the plasma has taken him all over the world and has led to insights that can help scientists control the plasma, a crucial task in creating fusion energy. Diallo is also known as an innovator in forging collaborations with companies and has served as a mentor to numerous early-career scientists.

Diallo said he is delighted to receive the award after an 11-year career at PPPL. “I’m incredibly honored by this fellowship,” said Diallo. “My gratitude goes to the Lab as well as to all my colleagues. I’m indebted to everyone at the Lab from the technicians to the administrators and especially my mentors and supervisors who gave me the room to develop and grow. I am also grateful to my family for their support.”

Diallo’s work focuses on the edge of the plasma called the pedestal where bursts of intense heat due to edge localized modes or ELMs occur. Measuring and analyzing this area is difficult because the edge is just a few inches wide and difficult to probe. Understanding ELMs can help scientists understand how to control these surges, which can expel the plasma that could damage the inner walls of donut-shaped fusion devices called tokamaks, such as PPPL’s National Spherical Torus Experiment – Upgrade (NSTX-U), and ITER, the massive fusion device under construction in France.

Diallo and his collaborators have conducted experiments on numerous fusion experiments including Alcator C-Mod at MIT, the DIII-D National Fusion Facility at General Atomics in San Diego, California, the Korean Superconducting Tokamak Advanced Research (KSTAR), the Experimental Advanced Superconducting Tokamak (EAST) in China, and the Mega Ampere Spherical Tokamak (MAST) in the United Kingdom. Data from the experiments can be used to develop models that can predict the dynamics at the edge of the plasma.

Scientific superstar

Rajesh Maingi, deputy director of the NSTX-U Science Department, wrote in his letter recommending Diallo for the fellowship that Diallo is viewed as a “scientific superstar and emergent community leader, with extraordinary diagnostic and analytical skills.” Maingi noted that Diallo’s diagnostics are used throughout the world. “He is also a world leader in looking at fluctuations in turbulence at the very periphery of the plasma, which is very important because if you engineer that properly you’ll get a very good performance out of the core of the plasma.”

Diallo is keen to find laser-based approaches to simultaneously probe the electric and magnetic fields and as well as the neutral densities. Diallo and collaborators at Oak Ridge National Laboratory in Tennessee recently received a DOE grant to assess the feasibility of a laser-based approach to probe the electric and internal magnetic fields in the edge of tokamaks.

His research is also taking him in new directions. Diallo is in the process of setting up a laboratory to study the laser-plasma interaction relevant to extreme ultraviolet (EUV) lithography, the process used to etch computer chips in microelectronics. Advancing nanoscale fabrication for microelectronics and other industries of the future is part of PPPL’s expanded research mission.

In addition, Diallo is deputy director of the Innovation Network for Fusion Energy (INFUSE), aimed at facilitating collaborations between industry and DOE national laboratories to develop new approaches to fusion energy technology. The program is managed by Oak Ridge National Laboratory (ORNL) and directed by Dennis Youchison. The program offered grants to 12 collaborative projects with different companies when it began last year.

Diallo first came to PPPL early in his career as a National Undergraduate Fellowship Program intern at PPPL during the summer after graduating from the University of Montana with a physics degree. Originally from Burkina-Faso in West Africa, Diallo received a General Academic Studies Degree from the University of Ouagadougou in Burkina-Faso before finishing his degree in the United States. He has since served as a mentor to numerous students doing hands-on research through the DOE’s Summer Undergraduate Laboratory Internship (SULI) program at PPPL. “He’s very good at mentoring early-career people,” Maingi said.

He went on to earn a Ph.D. in physics from the University of Iowa. Diallo was a post-doctoral fellow at the École Polytechnique Fédérale de Lausanne in Switzerland. Before coming to PPPL, he was a research fellow at the Australian National Laboratory’s Plasma Research Laboratory.