Variations in plume activity reveal the dynamics of water-filled faults on Enceladus

Abstract After discovering a remarkable jet activity above Enceladus' south-polar terrain, the Cassini mission demonstrated the existence of a subsurface water ocean with a unique sampling opportunity through flybys. Diurnal variations in the observed brightness of the plume suggest a tidal origin, although the existence and timing of two activity maxima seem to contradict stress analysis predictions. By combining a 3D global model of tidal deformation of the fractured ice shell with a 1D local model of transport processes within south-polar faults, we provide a self-consistent picture of mass flux that matches the observed plume activity. Considering shear-modulated jet flow and stress-modulated porous flow simultaneously explains both the apparent discrepancy between vapour and solid emission rates and the observed fractionation of the various icy particle families. This lays the ground for the optimal design of JWST observations of Enceladus' plume and future particle sampling strategies.