Jakub Bulička from the Institute of Physics of the Czech Academy of Sciences has taken third place in the best diploma thesis category of the Werner von Siemens Award - one of the most prestigious prizes for student research in the Czech Republic. His thesis was supervised by Libor Juha and defended at the Faculty of Nuclear Sciences and Physical Engineering at CTU in Prague.
The student and the supervisor work in the Department of Radiation and Chemical Physics at the Institute of Physics, which studies how high-power lasers produce plasmas able to trigger fusion of light nuclei and investigates which materials could withstand the conditions inside future fusion reactors. The award-winning thesis belongs to the latter area.
Where the energy comes from
A fusion reactor generates energy much the way the Sun does: high-power lasers compress and heat a small fuel capsule to extremely high pressures and temperatures, initiating a thermonuclear reaction that releases a tremendous amount of energy. The appeal is obvious: fusion fuel is plentiful, the reaction produces no greenhouse gases, and it generates no long-lived radioactive waste.
But all that energy must go somewhere. It escapes in the form of neutrons, alpha particles, and other reaction products that fly outward and slam into the chamber walls and the final optics. Every single pulse subjects these components to enormous stresses, which they must repeatedly withstand throughout the reactor’s service lifetime. So before fusion power can move from experimental facilities to the electricity grid, we must answer one fundamental question: what materials can survive in such a severe environment?
Simulating it in the laboratory
The student decided to replicate these conditions in the laboratory. He exposed various materials to energetic radiation - specifically, photons from an extreme ultraviolet laser - and observed how an increasing number of ions were released from the radiation-damaged surface. He then used the measured ion signals to determine the damage thresholds of the tested materials.
"One of the reasons Jakub's diploma thesis stands out is that he conducted a large part of his research abroad, at Colorado State University" says his supervisor. And the findings turned out to be genuinely surprising. The most radiation-resistant material was not tungsten, currently the preferred choice for first walls of fusion reactors, but certain ceramics based on boron nitride, which exhibited significantly higher resistance and could influence the design of future reactors.
The award-winning results were achieved through collaboration among several research institutions: in addition to the Institute of Physics of the Czech Academy of Sciences and Colorado State University, researchers from the Institute of Plasma Physics of the Czech Academy of Sciences and the European XFEL research centre in Schenefeld, Germany -which operates one of the world’s most powerful x-ray free-electron lasers - contributed to the project. In addition to the Colorado State University in Fort Collins, the Faculty of Nuclear Sciences and Physical Engineering of CTU and the Faculty of Mathematics and Physics of Charles University played a significant role in the student’s education and scientific training.
You can watch the video profile of Jakub Bulička’s award here.
Photo: Kurt Neubauer / Werner von Siemens Awards
