Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby

Abstract The BepiColombo mission offers a unique opportunity to investigate Mercury’s magnetosphere and its interaction with the solar wind. This study presents a model-based reference for ion and magnetic field observations during the sixth Mercury flyby (MSB6) on January 8, 2025, using the global...

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Main Authors: Daniel Teubenbacher, Yasuhito Narita, Ali Varsani, Daniel Schmid, Gunter Laky, Willi Exner
Format: Article
Language:English
Published: SpringerOpen 2025-07-01
Series:Earth, Planets and Space
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Online Access:https://doi.org/10.1186/s40623-025-02231-8
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author Daniel Teubenbacher
Yasuhito Narita
Ali Varsani
Daniel Schmid
Gunter Laky
Willi Exner
author_facet Daniel Teubenbacher
Yasuhito Narita
Ali Varsani
Daniel Schmid
Gunter Laky
Willi Exner
author_sort Daniel Teubenbacher
collection DOAJ
description Abstract The BepiColombo mission offers a unique opportunity to investigate Mercury’s magnetosphere and its interaction with the solar wind. This study presents a model-based reference for ion and magnetic field observations during the sixth Mercury flyby (MSB6) on January 8, 2025, using the global 3D hybrid plasma code AIKEF. Simulations include 12 solar wind and IMF conditions, incorporating a kinetic treatment of ions and a self-consistent sodium exosphere. Differential ion energy spectra are computed along the high-latitude MSB6 trajectory for both solar wind-originated protons and exospheric sodium ions. Five distinct plasma regions are identified, including a southern plasma mantle as the transition region from magnetosheath plasma to lobe plasma; a southern lobe region characterized by $$\textbf{E} \times \textbf{B}$$ E × B convection; the central tail current sheet with a fast planetward plasma flow due to magnetic reconnection; a northern mantle or cusp-like region containing escaping sodium ions; and a faint pick-up population upstream of the bow shock. Ion energies reach up to 10 keV for protons and 30 keV for sodium under strong solar wind conditions. Notably, the high-latitude plasma mantle exhibits a clear energy dispersion-like feature, with its structure sensitive to solar wind dynamic pressure. Stronger solar wind input leads to steeper ion energy gradients in the spectra, while weaker conditions result in broader mantle structures ranging from 400 to 2000 km (3–26 local proton gyroradii). Cross-magnetospheric electric potentials of $$\phi _{\text{tail}} = 14{-}32\,\text{kV}$$ ϕ tail = 14 - 32 kV align with observational estimates. These findings provide critical insights into Mercury’s magnetospheric dynamics and form a foundation for interpreting BepiColombo’s observations. Graphical Abstract
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spelling doaj-art-60d9d22fb7cb46e499c133dcad571c772025-08-20T04:01:53ZengSpringerOpenEarth, Planets and Space1880-59812025-07-0177111210.1186/s40623-025-02231-8Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flybyDaniel Teubenbacher0Yasuhito Narita1Ali Varsani2Daniel Schmid3Gunter Laky4Willi Exner5Space Research Institute Graz, Austrian Academy of SciencesInstitute of Theoretical Physics, Technische Universität BraunschweigSpace Research Institute Graz, Austrian Academy of SciencesSpace Research Institute Graz, Austrian Academy of SciencesSpace Research Institute Graz, Austrian Academy of SciencesMax-Planck-Institut für SonnensystemforschungAbstract The BepiColombo mission offers a unique opportunity to investigate Mercury’s magnetosphere and its interaction with the solar wind. This study presents a model-based reference for ion and magnetic field observations during the sixth Mercury flyby (MSB6) on January 8, 2025, using the global 3D hybrid plasma code AIKEF. Simulations include 12 solar wind and IMF conditions, incorporating a kinetic treatment of ions and a self-consistent sodium exosphere. Differential ion energy spectra are computed along the high-latitude MSB6 trajectory for both solar wind-originated protons and exospheric sodium ions. Five distinct plasma regions are identified, including a southern plasma mantle as the transition region from magnetosheath plasma to lobe plasma; a southern lobe region characterized by $$\textbf{E} \times \textbf{B}$$ E × B convection; the central tail current sheet with a fast planetward plasma flow due to magnetic reconnection; a northern mantle or cusp-like region containing escaping sodium ions; and a faint pick-up population upstream of the bow shock. Ion energies reach up to 10 keV for protons and 30 keV for sodium under strong solar wind conditions. Notably, the high-latitude plasma mantle exhibits a clear energy dispersion-like feature, with its structure sensitive to solar wind dynamic pressure. Stronger solar wind input leads to steeper ion energy gradients in the spectra, while weaker conditions result in broader mantle structures ranging from 400 to 2000 km (3–26 local proton gyroradii). Cross-magnetospheric electric potentials of $$\phi _{\text{tail}} = 14{-}32\,\text{kV}$$ ϕ tail = 14 - 32 kV align with observational estimates. These findings provide critical insights into Mercury’s magnetospheric dynamics and form a foundation for interpreting BepiColombo’s observations. Graphical Abstracthttps://doi.org/10.1186/s40623-025-02231-8Mercury’s magnetosphereGlobal 3D hybrid plasma simulationStar–planet interactionSpace plasma physics
spellingShingle Daniel Teubenbacher
Yasuhito Narita
Ali Varsani
Daniel Schmid
Gunter Laky
Willi Exner
Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
Earth, Planets and Space
Mercury’s magnetosphere
Global 3D hybrid plasma simulation
Star–planet interaction
Space plasma physics
title Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
title_full Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
title_fullStr Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
title_full_unstemmed Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
title_short Ion-kinetic modeling of Mercury’s magnetosphere: a reference for BepiColombo’s sixth flyby
title_sort ion kinetic modeling of mercury s magnetosphere a reference for bepicolombo s sixth flyby
topic Mercury’s magnetosphere
Global 3D hybrid plasma simulation
Star–planet interaction
Space plasma physics
url https://doi.org/10.1186/s40623-025-02231-8
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