Scientists resolved a 20-year mystery about how diamond melts under extreme pressure, with implications for fusion energy
Lawrence Livermore National Laboratory researchers documented how diamond melts at pressures three times greater than Earth's core, resolving a 20-year discrepancy between lab measurements and theory. Per LLNL and Nature Physics.
Researchers at Lawrence Livermore National Laboratory (LLNL) used laser-driven shock compression at the University of Rochester's Omega Laser Facility to study how diamond melts at pressures three times greater than Earth's core and temperatures hotter than the sun's surface, sustained for about one billionth of a second. The experiment resolved a roughly 20-year discrepancy between lab measurements and theoretical models, which had disagreed on diamond's melting temperature by more than 1,000 degrees. New X-ray diffraction data finally matched simulations, confirming diamond stays in its crystal structure until it melts directly into liquid carbon, in which it floats due to the liquid's higher density. Applied to inertial confinement fusion at LLNL's National Ignition Facility, the findings suggest a slower initial laser shock could still fully melt a fusion capsule's diamond shell, potentially tripling energy gain. The study, led by LLNL scientists Marius Millot and Jon Eggert, was published in Nature Physics. Sources: Lawrence Livermore National Laboratory, ScienceDaily.