Internally heated porous convection: an idealised model for Enceladus' hydrothermal activity

TL;DR

This study develops an idealised model of internally-heated porous convection to understand hydrothermal activity in Enceladus' interior, providing scaling laws for heat transport and flow intensity relevant to icy moons.

Contribution

It introduces a simplified theoretical framework for internally-heated porous convection, deriving general laws for temperature and flow in icy moon interiors.

Findings

Quantifies heat-transport efficiency in porous convection.

Derives laws governing temperature and hydrothermal velocities.

Provides insights into heat-flux anomalies at icy moon surfaces.

Abstract

Recent planetary data and geophysical modelling suggest that hydrothermal activity is ongoing under the ice crust of Enceladus, one of Saturn's moons. According to these models, hydrothermal flow in the porous, rocky core of the satellite is driven by tidal deformation that induces dissipation and volumetric internal heating. Despite the effort in the modelling of Enceladus' interior, systematic understanding---and even basic scaling laws---of internally-heated porous convection and hydrothermal activity are still lacking. In this article, using an idealised model of an internally-heated porous medium, we explore numerically and theoretically the flows that develop close and far from the onset of convection. In particular, we quantify heat-transport efficiency by convective flows as well as the typical extent and intensity of heat-flux anomalies created at the top of the porous layer. With our idealised model, we derive simple and general laws governing the temperature and hydrothermal velocity that can be driven in the oceans of icy moons. In the future, these laws could help better constraining models of the interior of Enceladus and other icy satellites.