A Systematic Exploration of Nested Dynamos

Planetary magnetic fields are traditionally modelled as the result of convective dynamo action within a single, well-defined electrically conducting region (e.g., the liquid iron core inside a terrestrial planet or the metallic hydrogen layer inside a gas giant). However, recent theoretical and observational developments suggest that many planetary bodies may host nested dynamo regions, where multiple layers of convection in electrically conducting fluids can support dynamo action. In particular, Juno revealed that in Jupiter there is likely a deep dynamo region in its dilute core as well as a secondary dynamo region, sitting atop a compositionally stable, stratified layer. In this study, we present a suite of three-dimensional magnetohydrodynamic (MHD) numerical models exploring the behaviour and evolution of such nested dynamos.

Our MHD dynamo simulations explore the fundamental differences between nested and single-layer dynamos in a systematic way. These nested dynamos represent the next frontier of planetary dynamo investigations. They are crucial for understanding the dynamics and evolution of these multi-layered bodies and their space environments, which are characterised by their internal magnetic fields.