DOI: 10.5281/zenodo.14565768
title: Data for "The Spatiotemporal Structure of Induced Magnetic Fields in Callisto's Plasma Environment due to their Propagation with MHD Modes" by Strack & Saur

description: This dataset contains data from the publication Strack & Saur, 2024 (https://doi.org/10.1029/2024JA033235), including the output of our MHD model as well as processed data used in Figures 4, 5, and 6.

 

We use a Cartesian and a spherical coordinate system, both with the origin at the geometric center of Callisto. In the Cartesian system, the z-axis is parallel to Jupiter’s rotation axis, the y-axis points to the center of Jupiter and the x-axis, which completes the right-handed coordinate system, is approximately in direction of Callisto's orbital motion. In the spherical coordinate system, phi=0° is defined on the Jupiter-facing meridian (positive y-axis) and is counted in an easterly direction, i.e., phi=90° is the upstream direction (negative x-axis). Theta is taken from the positive z-axis.





Simulation Output


The PLUTO simulation code (v4.4, Mignone et al. 2007, http://plutocode.ph.unito.it) was used for the numerical solution of the MHD model. A description of the model equations, boundary conditions and simulation process is given Strack & Saur, 2024.


The simulations were performed in spherical geometry (r, theta, phi). Each "*.flt" output file contains the model variables on the simulation grid for a single time step. The respective simulation grid is specified in the "grid.out" file. The model variables are:



rho: Plasma mass density

vx1: Plasma bulk velocity, r component

vx2: Plasma bulk velocity, theta component

vx3: Plasma bulk velocity, phi component

Bx1: Magnetic field, r component

Bx2: Magnetic field, theta component

Bx3: Magnetic field, phi component

prs: Thermal plasma pressure




Each simulation output file also contains the following additional variables:



Bpx1: In our case, this is the same as Bx1

Bpx2: In our case, this is the same as Bx2

Bpx3: In our case, this is the same as Bx3

Jx1: Electric current density, r component

Jx2: Electric current density, phi component

Jx3: Electric current density, theta component


In the output files, all values are in normalized units. The normalization factors (in CGS units) are:



norm_r = 2410e3 cm

norm_t = 1.255e1 s

norm_rho = 1.594e-24 g/cm^3

norm_v = 1.92e7 cm/s

norm_B = 8.593e-05 Gauss

norm_prs = 5.877e-10 dyne/cm^3

norm_J = 8.508e-04 statA/cm^2


Since the simulation output files are in PLUTO's binary ".flt" format, we provide the Python script "read_data.py" to read the simulation data and grid specifications.


We provide the following simulation data:


For Section 4 in Strack & Saur, 2024



`./symmetric_model_reference`: The reference simulation, i.e., moon-magnetosphere interactions only`./symmetric_model_full_A075`: The (main) full simulation with A=0.75, i.e., moon-magnetosphere interactions and induced magnetic field`./symmetric_model_full_A025`: The full simulation with A=0.25`./symmetric_model_full_A050`: The full simulation with A=0.50`./symmetric_model_full_A100`: The full simulation with A=1.00


For Section 5 in Strack & Saur, 2024





`./C03_high_density_reference`: The reference simulation for the C03 flyby with the higher initial plasma mass density

`./C03_high_density_full`: The full simulation with A=0.85 for the C03 flyby with the higher initial plasma mass density

`./C03_low_density_reference`: The reference simulation for the C03 flyby with the lower initial plasma mass density

`./C03_low_density_full`: The full simulation with A=0.85 for the C03 flyby with the lower initial plasma mass density

`./C09_high_density_reference`: The reference simulation for the C09 flyby with the higher initial plasma mass density

`./C09_high_density_full`: The full simulation with A=0.85 for the C09 flyby with the higher initial plasma mass density

`./C09_low_density_reference`: The reference simulation for the C09 flyby with the lower initial plasma mass density

`./C09_low_density_full`: The full simulation with A=0.85 for the C09 flyby with the lower initial plasma mass density




Note that in the simulation data that is provided for the symmetric model (Section 4), the output numbers of the data files are different. This is because a higher output frequency was used for the reference simulation and the A=0.75 full simulation. All output files for the symmetric full simulations refer to the end of the propagation time span shown in Figure 4. For the reference simulation, the output is provided at the beginning and end of this time span.

 





Processed Data

In addition to the simulation output, we provide processed data used in Figures 4, 5 and 6 of Strack & Saur, 2024.

The directory `./data_figure_4_and_5` contains the following files for each of the four panels in Figure 4:



`fig4_panel_*_reference.csv`: The magnetic field of the reference simulation for the respective profile. Provided are the mean, minimum, and maximum values of each component (Bx, By, Bz) in the analyzed time period.

`fig4_panel_*_full_Bx.csv`: The time series of the Bx magnetic field component of the full simulation for the respective profile. Each column contains values for a different position (given in the first row) and each row contains values for a different point in time (given in the first column).

`fig4_panel_*_full_By.csv`, `fig4_panel_*_full_Bz.csv`: The time series of the By and Bz magnetic field components, respectively.


The data given for panels a and b are also used in Figure 5.

The directory `./data_figure_6` contains a single file `fig6_sample_data.csv` with the data used for Figure 6.



The first three columns of the file give the Cartesian coordinates of the sample points

"B_sec_infinity" is the magnitude of the induced magnetic dipole field in a vacuum environment with A=1.0 (Equation 1)

"dB_reference" is the numerical variability of the reference simulation in its approximately stationary state

The last four columns (e.g. "B_sec_A025") contain the transport altered induced magnetic field magnitudes in the plasma environment for a true dipole amplitude of A=0.25, A=0.50, A=0.75, and A=1.00


Note that length, time and magnetic field in the processed data are given in units of Callisto radii (Rc), seconds and nanotesla.


References:



Mignone, A., Bodo, G., Massaglia, S., Matsakos, T., Tesileanu, O., Zanni, C., & Ferrari, A. (2007). PLUTO: A Numerical Code for Computational Astrophysics. The Astrophysical Journal Supplement Series, 170(1), 228–242. https://doi.org/10.1086/513316


Strack, D., Saur, J. (2024). The Spatiotemporal Structure of Induced Magnetic Fields in Callisto's Plasma Environment Due to Their Propagation With MHD modes. Journal of Geophysical Research: Space Physics, 129(12),  https://doi.org/10.1029/2024JA033235