Magnetic field induced by convective flow in Europa's subsurface ocean

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10508250" target="_blank" >RIV/00216208:11320/25:10508250 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=AnOIqt54-a" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=AnOIqt54-a</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.icarus.2024.116375" target="_blank" >10.1016/j.icarus.2024.116375</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Magnetic field induced by convective flow in Europa's subsurface ocean

Popis výsledku v původním jazyce

Movements of Europa in Jupiter&apos;s magnetic field generate an induced magnetic field in the moon&apos;s interior. Its measurements by the Galileo space probe led to the discovery of Europa&apos;s subsurface ocean. However, interactions of the ocean flow with Jupiter&apos;s background magnetic field also generate the motionally induced electrical currents in the ocean and the corresponding ocean-induced magnetic field (OIMF), which has not yet been studied in detail. A single study estimated the OIMF &lt;= 20nT using a simplified scaling relation. In this paper, we revisit this estimate using a physically consistent modeling setup. Based on the numerical simulations of ocean convection, we show that two modes can exist in Europa&apos;s ocean. Mode I is dominated by a prograde zonal flow at the equator with negligible radial and meridional flows. Mode II is characterized by Hadley-like meridional circulation cells in both hemispheres and a retrograde zonal flow at the equator. The scaling analysis based on our dataset strongly indicates that Mode II is appropriate for Europa&apos;s ocean with velocities around 0.3 m/s. We then calculate Europa&apos;s OIMF using a time-domain EM induction solver, which properly accounts for self-induction and diffusion of the magnetic field in the silicate and ice layers, and implicitly covers the full temporal spectrum. Our calculations suggest that even under the most favorable circumstances ( 150 km thick ocean with a conductivity of 18 S/m located under a 1 km thick ice layer) the magnitude of Europa&apos;s OIMF forced by the flow in Mode II is approximately 1 nT, at the lower bound of the sensitivity of the Europa Clipper measurements and more than one order of magnitude smaller than previously predicted. The discrepancy is primarily caused by amore sluggish ocean flow and a correct treatment of EM induction. Moreover, Europa&apos;s OIMF is affected by the electrical conductivity and thickness of ice and ocean, which we demonstrate in a parametric study.

Název v anglickém jazyce

Magnetic field induced by convective flow in Europa's subsurface ocean

Popis výsledku anglicky

Movements of Europa in Jupiter&apos;s magnetic field generate an induced magnetic field in the moon&apos;s interior. Its measurements by the Galileo space probe led to the discovery of Europa&apos;s subsurface ocean. However, interactions of the ocean flow with Jupiter&apos;s background magnetic field also generate the motionally induced electrical currents in the ocean and the corresponding ocean-induced magnetic field (OIMF), which has not yet been studied in detail. A single study estimated the OIMF &lt;= 20nT using a simplified scaling relation. In this paper, we revisit this estimate using a physically consistent modeling setup. Based on the numerical simulations of ocean convection, we show that two modes can exist in Europa&apos;s ocean. Mode I is dominated by a prograde zonal flow at the equator with negligible radial and meridional flows. Mode II is characterized by Hadley-like meridional circulation cells in both hemispheres and a retrograde zonal flow at the equator. The scaling analysis based on our dataset strongly indicates that Mode II is appropriate for Europa&apos;s ocean with velocities around 0.3 m/s. We then calculate Europa&apos;s OIMF using a time-domain EM induction solver, which properly accounts for self-induction and diffusion of the magnetic field in the silicate and ice layers, and implicitly covers the full temporal spectrum. Our calculations suggest that even under the most favorable circumstances ( 150 km thick ocean with a conductivity of 18 S/m located under a 1 km thick ice layer) the magnitude of Europa&apos;s OIMF forced by the flow in Mode II is approximately 1 nT, at the lower bound of the sensitivity of the Europa Clipper measurements and more than one order of magnitude smaller than previously predicted. The discrepancy is primarily caused by amore sluggish ocean flow and a correct treatment of EM induction. Moreover, Europa&apos;s OIMF is affected by the electrical conductivity and thickness of ice and ocean, which we demonstrate in a parametric study.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10500 - Earth and related environmental sciences

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Icarus

ISSN

0019-1035

e-ISSN

1090-2643

Svazek periodika

429

Číslo periodika v rámci svazku

January

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

14

Strana od-do

116375

Kód UT WoS článku

001373511100001

EID výsledku v databázi Scopus

2-s2.0-85210721752