New Constraint On Europa’s Ice Shell: Magnetic Signature From The Ocean

Jupiter’s moon Europa is smaller than Earth’s moon yet may contain more than twice as much liquid water as all of Earth’s oceans combined. Scientists believe that under its icy surface, Europa features a global saltwater ocean, perhaps 40 to 100 miles (60 to 150 kilometers) deep. Further inward, a rocky mantle and metallic core are likely. — NASA larger image

Jupiter’s icy moons are believed to host subsurface liquid oceans, and among them, Europa stands out as one of the most promising candidates for extraterrestrial life.

Yet, the processes driving oceanic flows beneath its ice shell, as well as the factors controlling the thickness of this ice, remain incompletely understood. One especially distinctive feature of Europa is that its salty ocean is electrically conducting and thus influenced by Jupiter’s time-varying magnetic field, which is believed to drive a large-scale zonal flow.

Here, we examine hos this magnetically-induced jet affects both the heat flux and the dynamics of the convective flow within Europa’s ocean. We first show that the magnetically-driven jet efficiently transports heat in stably stratified regions near the top of the ocean, and may alter the expected convective scaling laws in deeper layers.

Second, by analysing the latitudinal distribution of heat flux and relating it to ice-thickness variations, we make predictions that can be compared with current observations.

In anticipation of the upcoming JUICE and Europa Clipper missions, we discuss how improved measurement precision could help further constrain the ocean’s properties and refine our model-based forecasts.

Florentin Daniel, Ludovic Petitdemange, Christophe Gissinger

Comments: 15 pages, 7 figures, 1 table, accepted for publication in Icarus
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2509.10903 [astro-ph.EP] (or arXiv:2509.10903v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2509.10903
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Journal reference: Icarus 2025
Related DOI:
https://doi.org/10.1016/j.icarus.2025.116792
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Submission history
From: Florentin Daniel
[v1] Sat, 13 Sep 2025 17:05:14 UTC (436 KB)
https://arxiv.org/abs/2509.10903
Astrobiology,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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