Upvote on-topic answers supported by reputable sources and scientific research.Answer questions with accurate, in-depth explanations, including peer-reviewed sources where possible.(U.K.).Please read our guidelines and FAQ before posting Collaborators included scientists from University of Rostock (Germany), University of Warwick (U.K.), GSI Helmholtz Center for Heavy Ion Research (Germany), University of California Berkeley, SLAC National Accelerator Laboratory, Helmholtz-Zentrum Dresden-Rossendorf (Germany), University of Lyon (France), Los Alamos National Laboratory, Imperial College London (U.K.), and First Light Fusion Ltd. The pioneering research was the result of an international collaboration to develop x-ray Thomson scattering at the NIF as part of LLNL's Discovery Science program. Improved predictive capabilities are urgently needed not only for astrophysics but also for further progress toward controlled nuclear fusion which would allow to harvest the energy source of the stars for humanity." The ionization in dense plasmas is a key parameter as it affects the equation of state, thermodynamic properties, and radiation transport through opacity."Īssociate Professor Dirk Gericke, University of Warwick, Department of Physics, added: "Having created and diagnosed these extreme pressures in the laboratory gives an invaluable benchmark for our theoretical models. Our work opens new avenues for studying and modeling the behavior of matter under extreme compression. ![]() LLNL physicist Tilo Döppner, who led the project, said: "By recreating extreme conditions similar to those inside giant planets and stars, we were able to observe changes in material properties and electron structure that are not captured by current models. Additionally, the study uncovered unexpectedly weak elastic X-ray scattering, indicating reduced localization of the remaining electron, that is a new stage shortly before all electrons become free and thus revealing the pathways to a fully ionised state. The findings revealed that, following strong heating and compression, at least three out of four electrons in beryllium transitioned into conducting states, that is, they can move independent from the nuclear cores of the atoms. The highly compressed metal shell (made of beryllium) was then analysed using X-rays to reveal its density, temperature, and electron structure. ![]() As the outside of the shell rapidly expanded due to the heating, the inside was driven inwards - reaching temperatures around two million kelvins (1.9m degrees Celsius) and pressures up to three billion atmospheres - creating a tiny piece of matter as found in dwarf stars for just a few nanoseconds. They focused 184 laser beams on a cavity, converting the laser energy into X-rays that heated a 2mm metal shell placed in the centre. The international research team used NIF to generate the extreme conditions necessary for pressure-driven ionisation. They investigated the properties and behaviour of matter under extreme compression, offering important implications for astrophysics and nuclear fusion research. Through their research at the Lawrence Livermore National Laboratory (LLNL), US, the team provide new insights on the complex process of pressure-driven ionisation in giant planets and stars. In a new experiment published today in Nature, scientists have done just that using the largest and most energetic laser in the world, the National Ignition Facility (NIF). The only way to study this complex process in the laboratory is to dynamically compress matter to extreme densities which requires very large energy inputs in a very short time. Progress in this grand scientific challenge relies heavily on numerical modelling and the ionisation balance in high-pressure systems is of central importance. This process has been heralded as an unlimited, carbon free energy source - by using large excess energy generated by the fusion reactions to generate electricity. However, this process is not well understood, and the extreme states of matter required are very difficult to create in the laboratory limiting the predictive power required to model celestial objects.Įxtreme conditions also occur in laser-driven fusion experiments where hydrogen atoms are fused under high pressures and temperatures to helium, a heavier element. While ionisation in burning stars is primarily determined by temperature, pressure-driven ionization dominates in cooler stellar objects. The material properties of such matter are mostly determined by the degree of ionisation of the atoms. ![]() The extreme pressures generated are strong enough to charge of atoms and generate free electrons, in a process known as ionisation. Matter in the interior of giant planets and some relatively cool stars is highly compressed by the weight of the layers above.
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