Internal and External Jovian Magnetic Fields: Community Code to Serve the Magnetospheres of the Outer Planets Community

We report on a new international community coding project to provide shared scientific computer code that performs common calculations to aid in planning scientific observations, modeling, and data analysis. We have developed code which calculates Jupiter's internal and external magnetic fields. All magnetic field model code is provided in four programming languages (C++, IDL, MATLAB and Python). The code is freely available on GitHub. For Jupiter's internal magnetic field, we present a number of spherical harmonic internal magnetic field models. These include JRM33, the latest Jupiter internal magnetic field model (Connerney et al. in J. Geophys. Res., Planets 127(2):e07055, 2022), as well as older jovian models (e.g. JRM09 (Connerney et al. in Geophys. Res. Lett. 45(6):2590-2596, 2018), O6 (Connerney in Planetary Radio Emissions III, pp. 13-33, 1992), VIP4 (Connerney et al. in J. Geophys. Res. 103(A6):11,929-11,940, 1998) and VIPAL (Hess et al. in J. Geophys. Res. Space Phys. 116(A5):A05217, 2011)). The internal magnetic field code can be easily modified for other planets by simply inputting another spherical harmonic magnetic field model. We have also developed code to calculate the magnetic field perturbations due to the azimuthal and radial currents flowing externally around Jupiter in the jovian magnetodisc according to the model of Connerney et al. (J. Geophys. Res. 86(A10):8370-8384, 1981; J. Geophys. Res. Space Phys. 125(10):e28138, 2020). The internal and external magnetic field codes can be combined to model the magnetic field in Jupiter's magnetosphere. Finally, we provide field-line tracing software (C++ and a Python wrapper for C++) that utilizes the internal and external magnetic field models. The software can be used to trace along field lines from any position in the jovian magnetosphere to, for example, the ionosphere or an equator, and can also be utilized at different planets.