  The Juno mission will measure Jupiter's magnetic field with unprecedented
precision and provide a wealth of additional data that will allow to constrain
the planet's interior structure and dynamics. Here we analyse 66 numerical
simulations in order to explore the sensitivity of the dynamo-generated
magnetic field to the planets interior properties. The degree l=4 field model
VIP4 and up-to-date interior models based on ab initio simulations serve as
benchmarks. Our results suggest that VIP4-like magnetic fields can be found for
a number of different models. We find that whether we assume an ideal gas or
use the more realistic interior model based on ab initio simulations makes no
difference. However, two other factors are important. Low Rayleigh number leads
to strong axial dipole contribution while the axial dipole dominance is lost
when the convective driving is too strong. The required intermediate range that
yields Jupiter-like magnetic fields depends on the other system properties. The
second factor is the convective magnetic Reynolds number profile Rmc(r), a
product of the non-axisymmetric flow velocity and electrical conductivity. We
find that the depth where Rmc exceeds about 50 is a good proxy for the top of
the dynamo region. When the dynamo region sits too deep, the axial dipole is
once more too dominant due to geometric reasons. We extrapolated our results to
Jupiter and the result suggests that the Jovian dynamo extends to 95% of the
planetary radius.
  The zonal flows in our simulations are dominated by an equatorial jet largely
confined to the molecular layer. Where the jet reaches down to higher
electrical conductivities, it is gives rise to a secondary alpha-Omega dynamo
that modifies the dipole-dominated field produced deeper in the planet. This
secondary dynamo can lead to strong magnetic field patches at low latitudes
that seem compatible with the VIP4 model.
