Understanding dense hydrogen at planetary conditions

TL;DR

This paper reviews how high-pressure physics and experimental/theoretical studies of hydrogen and helium inform our understanding of planetary interiors, especially giant planets like Jupiter and Saturn.

Contribution

It connects planetary interior modeling with recent advances in high-pressure physics of hydrogen and helium, highlighting experimental and theoretical progress.

Findings

Summarizes key experiments on hydrogen and helium EOS and phase diagrams.

Reviews current models of Jupiter and Saturn's internal structures.

Emphasizes importance of high-pressure physics in planetary science.

Abstract

Materials at high pressures and temperatures are of great interest for planetary science and astrophysics, warm dense matter physics, and inertial confinement fusion research. Planetary structure models rely on our understanding of the behaviour of elements (and their mixtures) at exotic conditions that do not exist on Earth, and at the same time planets serve as natural laboratories for studying materials at extreme conditions. In this review we discuss the connection between modelling planetary interiors and high-pressure physics of hydrogen and helium. First, we summarise key experiments for determining the equation of state and phase diagram of hydrogen and helium as well as state-of-the-art theoretical approaches. We next briefly review our current knowledge of the internal structures of the giant planets in the Solar System, Jupiter and Saturn, and the importance of high pressure physics to their characterisation.