Chemical processes in the deep interior of Uranus.

The unusual magnetic fields of the planets Uranus and Neptune represent important observables for constraining and developing deep interior models. Models suggests that the unusual non-dipolar and non-axial magnetic fields of these planets originate from a thin convective and conducting shell of material around a stably stratified fluid core. Here, we present an experimental and computational study of the physical properties of a fluid representative of the interior of Uranus and Neptune. Our electrical conductivity results confirm that the core cannot be well mixed if it is to generate non-axisymmetric magnetic fields. The molecular dynamics simulations highlight the importance of chemistry on the properties of this complex mixture, including the formation of large clusters of carbon and nitrogen and a possible mechanism for a compositional gradient, which may lead to a stably stratified core.