Journal article
Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby
Geophysical research letters, Vol.49(24), e2022GL101688
12/28/2022
DOI: 10.1029/2022GL101688
Abstract
Abstract On 7 June 2021 the Juno spacecraft visited Ganymede and provided the first in situ observations since Galileo's last flyby in 2000. The measurements obtained along a one‐dimensional trajectory can be brought into global context with the help of three‐dimensional magnetospheric models. Here we apply the magnetohydrodynamic model of Duling et al. (2014, https://doi.org/10.1002/2013ja019554 ) to conditions during the Juno flyby. In addition to the global distribution of plasma variables we provide mapping of Juno's position along magnetic field lines, Juno's distance from closed field lines and detailed information about the magnetic field's topology. We find that Juno did not enter the closed field line region and that the boundary between open and closed field lines on the surface matches the poleward edges of the observed auroral ovals. To estimate the sensitivity of the model results, we carry out a parameter study with different upstream plasma conditions and other model parameters.
Plain Language Summary In June 2021 the Juno spacecraft flew close to Ganymede, the largest moon of Jupiter, and explored its magnetic and plasma environment. Ganymede's own magnetic field forms a magnetosphere, which is embedded in Jupiter's large‐scale magnetosphere, and which is unique in the solar system. The vicinity of Ganymede is separated into regions that differ in whether the magnetic field lines connect to Ganymede's surface at both or one end or not at all. These regions are deformed by the plasma flow and determine the state of the plasma and the location of Ganymede's aurora. We perform simulations of the plasma flow and interaction to reveal the three‐dimensional structure of Ganymede's magnetosphere during the flyby of Juno. The model provides the three‐dimensional state of the plasma and magnetic field, predicted locations of the aurora and the geometrical magnetic context for Juno's trajectory. These results are helpful for the interpretation of the in situ and remote sensing obtained during the flyby. We find that Juno did not cross the region with field lines that connect to Ganymede's surface at both ends. Considering possible values for unknown model parameters, we also estimate the uncertainty of the model results.
Key Points Our magnetohydrodynamic model illustrates the state of Ganymede's magnetosphere during Juno's flyby and locates its trajectory outside closed field lines The location of the open‐closed‐field line‐boundary is predicted and matches the poleward edges of the aurora as observed by Juno We investigate model uncertainties caused by incomplete knowledge of upstream conditions and other parameters
Details
- Title: Subtitle
- Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby
- Creators
- Stefan Duling - University of CologneJoachim Saur - University of CologneGeorge Clark - Johns Hopkins University Applied Physics LaboratoryFrederic Allegrini - Southwest Research InstituteThomas Greathouse - Southwest Research InstituteRandy Gladstone - The University of Texas at San AntonioWilliam Kurth - University of IowaJohn E. P. Connerney - Goddard Space Flight CenterFran Bagenal - Laboratory for Atmospheric and Space PhysicsAli H. Sulaiman - University of Minnesota
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.49(24), e2022GL101688
- DOI
- 10.1029/2022GL101688
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Grant note
- DOI: 10.13039/100010663, name: H2020 European Research Council, award: 884711; DOI: 10.13039/100008893, name: University of Iowa, award: 699041X; DOI: 10.13039/100000104, name: National Aeronautics and Space Administration; DOI: 10.13039/100011766, name: Southwest Research Institute
- Language
- English
- Date published
- 12/28/2022
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455541502771
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