Degree-1 magnetic excitation spectra for icy moons

Matlab .mat files each containing a struct named FTdata with the fields below, containing information about the spatially uniform (degree-1) magnetic oscillations applied to each moon by their parent planet as a function of frequency. Used for determining the strength of induced magnetic fields from the moons from an interior conductivity structure. This dataset is compatible for use with the PlanetProfile framework for calculating the strength of induced magnetic field based in bulk properties of a moon in question. Save the files into the MagneticInduction/FieldData directory.

Each .mat file contains a Matlab struct FTdata with the following fields:

• frequency - the excitation frequency at which oscillations occur in Hz. This is the independent variable for the other fields.
• Bx_fft - magnitude of the excitation field B_x component at each frequency of oscillation in nT.
• By_fft - magnitude of the excitation field B_y component at each frequency of oscillation in nT.
• Bz_fft - magnitude of the excitation field B_z component at each frequency of oscillation in nT.

All vector components are in IAU coordinates, such that at the body center, +x is directed toward the parent planet, +z is directed along the body spin axis, and +y is directed approximately opposite to the orbital velocity to complete the right-handed set.

Excitation fields are determined by evaluation of SPICE kernels over a years-long time series at the location of the body center. Position information is inserted into a magnetospheric model for the parent planet and a Fourier transform is calculated from the time series. These data are the results of the Fourier transform. The magnetic field models we use for each planet are:

• Jupiter - JRM09 + Connerney current sheet model (Connerney et al., 2018, 1981)
• Saturn - The model of Burton et al. (2010)
• Uranus - AH₅ model (Herbert, 2009)
• Neptune - The model of Connerney et al. (1991)