NEWS & EVENTS

Jupiter possesses the strongest magnetic field in the Solar System, carving out the largest solar system magnetosphere within the solar wind flow. Inside this system the magnetosphere is electrodynamically coupled to Galilean moons. Callisto, the outermost of the four Galilean moons, orbits its parent planet at a distance of 26.3  (radius of Jupiter  = 71492 km) within Jupiter’s equatorial (0.19° inclination). As the upstream Alfvén speed is larger than the flow speed, the interaction between Callisto and Jupiter’s magnetosphere is sub-Alfvénic, resulting in the formation of Alfvén wings. The interaction exhibits complexity, involving induction, magnetosphere-dipole interaction, and magnetosphere-ionosphere interaction. Callisto subsurface currents, induced by variable Jupiter dipole field, generates magnetic field perturbations detected by Galileo spacecraft. Callisto's orbital position continuously undergoes periodic variations in magnetosphere and current sheet. Additionally, the absence of intrinsic global magnetic field allows impinging magnetospheric plasma to couple with Callisto's ionosphere. This complexity implies significant challenges in understanding the magnetic field morphology and disentangling electromagnetic induction effects associated with the subsurface ocean. In this work, a newly developed 3D high-resolution global magnetohydrodynamic (MHD) model with high-resolving power numerical algorithms implemented in spherical coordinate is used to investigate the interaction between Callisto and the magnetospheric plasma of Jupiter.

Additional information: Mr. CAI Jinshu, caijinshu@connect.hku.hk