Research at the European XFEL: High energy density research on planetary interior conditions

Mixtures of light elements are predicted to be the major components in the depths of the ice giant planets Neptune and Uranus. Their dynamics, evolution, and interior structure are insufficiently understood, and models rely imperatively on data for equation-of-state and transport properties. At the extreme pressures and temperatures of a few 1000 Kelvin of planetary interiors, very peculiar properties are predicted for these mixtures, including superionic lattices, polymerizations, demixing, and phase separation reactions. These phenomena can influence the planet’s interior structure and need to be experimentally investigated. At European XFEL’s High Energy Density instrument (HED) Alessandra Ravasio from Ecole Polytechniques in Palaiseau, France, and Dominik Kraus from Universität Rostock in Germany had studied the formation of superionic water and ammonia structures in the presence of carbon. Their findings may help to explain the peculiar magnetic field observed for both planets and provide valuable input for exoplanet classification.