The role of the Hall effect in the global structure and dynamics of planetary magnetospheres: Ganymede as a case study

We present high-resolution Hall MHD simulations of Ganymede's magnetosphere demonstrating that Hall electric fields in ion-scale magnetic reconnection layers have significant global effects not captured in resistive MHD simulations. Consistent with local kinetic simulations of magnetic reconnec...

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Bibliographic Details
Published in:Journal of geophysical research. Space physics 2015-07, Vol.120 (7), p.5377-5392
Main Authors: Dorelli, J. C., Glocer, Alex, Collinson, Glyn, Tóth, Gábor
Format: Article
Language:English
Subjects:
Astrophysics
Current sheets
Drift
Dynamic structural analysis
Electric fields
Electromagnetism
Flyby missions
Ganymede
Geophysics
Hall effect
Hall MHD
Jupiter
Jupiter (planet)
Jupiter satellites
Kelvin-Helmholtz waves
Lunar And Planetary Science And Exploration
Lunar surface
Magnetic Reconnection
Magnetism
Magnetohydrodynamics
Magnetopause
Magnetosphere
Magnetospheres
Magnetospheric plasma
Magnetotails
Mathematical And Computer Sciences (General)
Moon
Moons
Physics Of Elementary Particles And Fields
Planetary magnetospheres
Simulation
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Summary:We present high-resolution Hall MHD simulations of Ganymede's magnetosphere demonstrating that Hall electric fields in ion-scale magnetic reconnection layers have significant global effects not captured in resistive MHD simulations. Consistent with local kinetic simulations of magnetic reconnection, our global simulations show the development of intense field-aligned currents along the magnetic separatrices. These currents extend all the way down to the moon's surface, where they may contribute to Ganymede's aurora. Within the magnetopause and magnetotail current sheets, Hall J x B forces accelerate ions to the local Alfven speed in the out-of-plane direction, producing a global system of ion drift belts that circulates Jovian magnetospheric plasma throughout Ganymede's magnetosphere. We discuss some observable consequences of these Hall-induced currents and ion drifts: the appearance of a sub-Jovian 'double magnetopause' structure, an Alfvenic ion jet extending across the upstream magnetopause, and an asymmetric pattern of magnetopause Kelvin-Helmholtz waves.
ISSN:2169-9380
2169-9402
DOI:10.1002/2014JA020951