Liquid lithium helps plasma maintain a hot edge

Feb. 6, 2024

Emerging research suggests it may be easier to use fusion as a power source if liquid lithium is applied to the internal walls of the device housing the fusion plasma.

Plasma, the fourth state of matter, is a hot gas made of electrically charged particles. Scientists at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) are working on solutions to efficiently harness the power of fusion to offer a cleaner alternative to fossil fuels, often using devices called tokamaks, which confine plasma using magnetic fields.

In recent experiments, a coating of liquid lithium added to the inside of the tokamak wall helped the plasma stay hot at its edge. Maintaining a hot edge is key to their unique approach, which the scientists hope will one day contribute to designs for a fusion power plant. 

Richard Majeski, a managing principal research physicist at PPPL and head of the research, noted that one of the greatest challenges in developing fusion energy is to build a viable wall for the device confining the plasma. PPPL is dedicated to finding solutions to this and other challenges to help bridge the gaps in bringing fusion energy to the power grid. “Although LTX-β is a very modest-sized spherical tokamak, it is the first and still the only plasma confinement device in the world with a core plasma completely contained by a liquid lithium wall,” said Majeski. “The results from LTX-β have been very promising — liquid lithium not only provides a wall that can withstand contact with a 2-million-degree plasma, it actually improves the performance of the plasma.”

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