How diamond rain occurs inside ice giants like Neptune

Physicists from the Lawrence Livermore National Laboratory (LLNL) have successfully recreated the process of diamond melting under ultra-high pressure in a laboratory setting. The study, published in Nature Physics, clarifies the mechanism behind "diamond rains" inside ice giants like Neptune and Uranus and suggests a method to increase energy yield in thermonuclear fusion. To conduct the experiment, researchers used the Omega Laser facility at the University of Rochester. By applying a powerful laser to evaporate the outer layer of a diamond sample, they generated a massive shock wave. For one billionth of a second, the pressure inside the crystal exceeded the pressure at the center of the Earth by three times, while temperatures reached levels characteristic of the Sun's surface. The process was monitored using ultra-fast X-ray diffraction. The experiment resolved a long-standing discrepancy between theoretical models and practical measurements. Previously, measured diamond melting temperatures differed from quantum-mechanical models by approximately 20%, a gap exceeding 1,000 Kelvins. The new data confirms the accuracy of contemporary quantum models.