A new study has improved understanding of diamond melting, which might also be relevant for achieving higher energy gain in laser-driven nuclear fusion. <\/p>\n
Researchers at Lawrence Livermore National Laboratory (LLNL) document how diamond melts under pressures three times greater than the conditions at the Earth\u2019s core.<\/p>\n
\u201cWe were able to take tiny diamond samples and shock compress them to temperatures hotter than the surface of the sun and to pressures higher than the center of Neptune and Uranus \u2014 and still measure atomic structure, temperature, density and optical reflectivity,\u201d said author and LLNL scientist Marius Millot.<\/p>\n
Applying findings to inertial confinement fusion could triple energy gain<\/p>\n
The study resolves two long-standing discrepancies in the field, finally matching experimental results to simulations based on quantum mechanics. Applying the findings to inertial confinement fusion could triple energy<\/a> gain, and the new understanding of diamond\u2019s high-pressure phases could reshape models of planetary interiors, according to<\/a> a press release.<\/p>\n Researchers also highlighted that diamond is more than a dazzling gem \u2014 the extremely hard form of carbon makes up the pellet that encases fuel for inertial confinement fusion, and scientists believe it rains down deep inside ice giant planets like Neptune and Uranus. In both cases, the material experiences enormous pressures. Until now, experiments and simulations have disagreed about how it actually behaves under those conditions.<\/p>\n The team also pointed out that LLNL has been studying diamond\u2019s extreme behavior for decades. Lab scientist Jon Eggert and colleagues pioneered high-pressure melting experiments about 20 years ago, when they observed that diamond\u2019s density increased when melting.<\/p>\n \u201cWhile this is rather unusual among most materials, we all know an example of such behavior,\u201d said LLNL scientist Marius Millot. <\/p>\n \u201cLiquid water is denser than ice, which makes ice cubes float. Jon\u2019s finding means that diamond would float in liquid carbon at high pressures.\u201d<\/p>\n While that work was a landmark in the field, it led to more questions. One in particular stumped the research community: there was a roughly 20% difference between the observed and predicted melting temperatures of diamond.<\/p>\n \u201cNo matter what the theorists did \u2014 even with the most advanced computer simulation techniques \u2014 they could not reproduce the experiments,\u201d said Millot.<\/p>\n