Phys.org reports:Future fusion power plants aim to recreate the heart of a star here on Earth to power our future energy needs. While the core fusion plasma will burn at hundreds of millions of degrees, the surrounding structural components must handle sudden, punishing heat loads that rival the extreme temperatures faced by spacecraft upon reentry into Earth's atmosphere. Copper and its alloys are primary candidates for handling these intense heat fluctuations, making it vital to understand exactly how the metal behaves when pushed to its melting point. Now, researchers at the Department of Energy's SLAC National Accelerator Laboratory and collaborators have captured a detailed, step-by-step look at copper atoms as they underwent extreme heating. Published in Nature Communications, the results revealed a key parameter that allowed copper's crystal lattice to melt steadily rather than collapse instantaneously, as earlier simulations predicted. "These results greatly improve the simulations we use to predict which materials have the best shot at surviving the extreme conditions of future fusion reaction chambers," said Mianzhen Mo, a SLAC staff scientist who led the research. "They also demonstrate the incredible, atomic-scale resolution imaging we can achieve at SLAC's electron camera...." Researchers use computer simulations, aided by AI and machine learning, to sift through innumerable combinations of elements and identify promising candidate materials for real-world testing. "Whether the copper melts slowly or suddenly collapses, by the time the researchers look, the sample resembles nothing more than a metallic brown puddle," the article points out. But SLAC's powerful electron camera captures atomic and molecular movements down to the femtosecond — a millionth of a billionth of a second — and revealed that at around 1,424 degreesC (2,595 degreesF) there was still gradual melting as the temperature rose beyond the superheating limit, with real-world conditions showing the atoms shifted and retained some order. "It's a straightforward solution," said Mianzhen Mo, a SLAC staff scientist who led the research. "But molecular dynamics simulations had been overlooking it for years. When you have complex simulations attempting to capture every aspect of reality, down to individual atoms, it takes real-world data to show you what's missing from the calculations."Read more of this story at Slashdot.