We present an application of the latest UCL-AGA magnetodisc model (MDISC) to the study of the magnetic and plasma conditions in the near-Ganymede space. By doing this, we provide a comparison with measurements from Juno’s most recent flyby of the Jovian moon, perijove 34 (PJ34). We find good agreement between the model results and the magnetometer data, pointing towards a hot plasma index value $K_h = \SI{2.719(24)e7}{\pascal\,\meter\,\tesla^{-1}}$ and an effective magnetodisc radius $r_{\text{max}} = \SI{79.5(11)}{}$ Jupiter radii for the Jovian magnetosphere, for the duration of the trajectory, suggesting a configuration with middling levels of expansion. We also predict the plasma conditions observed by Juno during the same flight-path, as well as the typical conditions over the orbit of Ganymede, with the magnetic and hot plasma pressures assuming dominant roles. Finally, these results are compared with functional fits of a compilation of Galileo flyby data obtained in the vicinity of Ganymede’s orbit, suggesting Juno experienced somewhat similar conditions, despite a systematic overestimation in magnetic field intensity in the near-Ganymede space.

The spatial and time characterisation of trapped charged particle trajectories in magnetospheres has been extensively studied using dipole magnetic field structures. Such studies have allowed the calculation of spatial quantities such as equatorial loss cone size as a function of radial distance, the location of the mirror points along particular field lines (’L shells’) as a function of the particle’s equatorial pitch angle, and time quantities such as the bounce period and drift period as a function of the radial distance and the particle’s pitch angle at the equator. In this study, we present analogous calculations for the ‘disc-like’ field structure associated with the giant rotation-dominated magnetosphere of Jupiter as described by the UCL/Achilleos-Guio-Arridge (UCL/AGA) magnetodisc model. We discuss the effect of the magnetodisc field on various particle parameters, and make a comparison with the analogous motion in a dipole field.