Geodynamo Initiation Through Heat Pipe Mode in Mantle Evolution Models

The magnetic field is needed for protecting the Earth from harmful solar radiation and plays a vital role in maintaining the planet's atmosphere. The geodynamo is the mechanism responsible for generating Earth's magnetic field, driven by convection in the liquid outer core. To sustain the geodynamo, heat transfer through the core-mantle boundary (CMB) into the mantle is necessary. It is hypothesized that before the formation of the inner core, a high heat flux across the CMB was necessary to start the magnetic field, which requires that the core and mantle be out of thermal equilibrium. This can either be due to excess heat in the core, or excess heat transport in the mantle. This research focuses on the mantle's role in controlling heat transport across the CMB, using numerical models of convection in the mantle. In particular, we investigate the role of core superheat and heat-pipe heat transport in the mantle. Simulations varied the core's specific heat to observe thermal disequilibrium across the CMB over time. Results indicate that higher specific heats result in higher heat fluxes, suggesting potential geodynamo starts. Another simulation involved a core superheated by 300 K relative to the mantle, using the same specific heat range. This showed two potential geodynamo initiations: one before and one after the heat pipe mode. This could indicate that planets can have a short-lived geodynamo and then transition into a long lived one. Future work will focus on exploring additional parameters influencing geodynamo initiation and refining current models.