The 13th Chandrasekhar Prize, awarded to researchers who contributed to advances in plasma physics, was given to Dr. Choongseok Chang, Senior Scientist at Princeton Plasma Physics Laboratory in the United States. He was highly evaluated for significantly advancing the understanding of heat conduction and exhaust in fusion reactors. The Division of Plasma Physics under the Association of Asia-Pacific Physical Societies (Mitsuru Kikuchi, Representative Director) announced the award.
Provided by Princeton Plasma Physics Laboratory
A fusion reactor is a device that artificially creates heavier atomic nuclei such as helium by fusing light atomic nuclei like hydrogen, similar to the mechanism by which the Sun shines. Research is progressing on these devices as prospective power plants of the future. Inside the reactor, ultra-high temperatures cause electrons to separate from atoms, creating a plasma state where ions and electrons fly around in a disorderly fashion. Chang is a leading researcher in unraveling these complex movements using theory and supercomputers.
In fusion reactors, "tokamak" is a mainstream system that confines plasma using strong, donut-shaped magnetic fields. In the early 1980s, Chang extensively elucidated the mechanism by which ions carry heat and escape outward in tokamaks, developing new formulas to replace conventional ones that had limitations. Further refining the formula together with another researcher, he established the "Chang-Hinton formula," which remains widely used today.
In ITER (International Thermonuclear Experimental Reactor), currently under construction in France, the "divertor," a component that removes impurities and heat from plasma, is extremely critical. Based on conventional data, concerns arose that heat would concentrate in a narrow area, causing thermal damage to "divertor plates" that receive the plasma. In response, Chang developed "XGC," a program calculating complex plasma movements, making it applicable to ITER. As a result, he clarified that plasma turbulence plays a different role in ITER from conventional expectations, allowing heat to disperse more widely than previously predicted. Furthermore, he developed a prediction model using machine learning regarding heat broadening. Confirming this prediction experimentally with an international research team, he contributes significantly to operational planning for ITER.
Provided by the ITER Organization
The official citation for the award reads: "For foundational and pioneering contributions to plasma physics and magnetic confinement fusion energy science, particularly the development of neoclassical transport theory represented by the widely used Chang-Hinton formula for ion thermal conductivity, the construction of the XGC multiscale and multiphysics gyrokinetic edge plasma code, and the prediction of divertor heat flux width broadening due to turbulence together with surrogate models for prediction, which are critical for ITER and future tokamak reactors." The announcement was made on August 31, and the award ceremony took place on October 12 at the 10th Asia-Pacific Conference on Plasma Physics held in Busan, South Korea.
Chang was born in Yecheon, South Korea, in 1951. He earned his bachelor's degree in physics at Seoul National University and his doctorate at the University of Texas at Austin. He served as a professor of physics at Korea Advanced Institute of Science and Technology (KAIST) from 1986 to 2011. In 2011, he moved to Princeton Plasma Physics Laboratory, becoming a Managing Principal Research Physicist leading a large research group under the U.S. Department of Energy. He retired last year and became a Senior Scientist, an honorary position. He spent most of his research career at KAIST and is known for nurturing many junior researchers.
The Chandrasekhar Prize commemorates Subrahmanyan Chandrasekhar (1910-1995), an Indian-born American astrophysicist who won the Nobel Prize in Physics in 1983 and contributed to plasma physics. The Division of Plasma Physics under the Association of Asia-Pacific Physical Societies established the award in 2014.
Provided by Princeton Plasma Physics Laboratory
Original article was provided by the Science Portal and has been translated by Science Japan.