Abstract
On June 7th, 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) 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.