Synthetic Observables of Helioseismic and Magnetic Imager

Version 1.0 (01/01/2026)

Irina Kitiashvili (irina.n.kitiashvili@nasa.gov)

Synthetic observational data of the FeI line (6173A), which is the operational wavelength of the Helioseismic and Magnetic Imager (HMI) 
onboard NASA's Solar Dynamics Observatory (SDO), represent 3D maps of solar 80x80Mm patches with spatial resolution of 100km at 
0 degrees (disk center), +/-30, +/-45, +/-60, and +/-75 degrees longitude (Kitiashvili 2026). Observer is located at the same latitude.
Each directory includes data sets of approximately 26.5 hours duration at a 45 sec time cadence. 
The model and additional synthetic data set can be extended on request. 

The data include continuum intensity and Doppler shift maps (units: cm/s) and profiles computed from Stokes profiles 
for a reference line at 6173 Angstrom (from the NIST Atomic Database Lines Data). 

To generate synthetic data, hydrodynamic simulations were used (Kitiashvili et al, 2023). In the radial direction, 
the model cover the 25 Mm of the uppermost layers of the convection zone and 1 Mm of the atmosphere. The horizontal size 
of the simulation domain is 80 x 80 Mm. 

Each file represents a 3D array (nx,ny,nt), where nx corresponds to the azimuthal direction (from East to West), 
ny is the meridional plane (Northward), and nt is time. These results were obtained using the StellarBox code (Wray et al., 2015, 2018), 
assuming a mean rotation period of 27.2753 days at 30 degrees latitude. The rotation was imposed using the F-plane approximation. 
The model is described in Kitiashvili et al. (2023). The data set has been used to study the center-to-limb effect (Kitiashvili 2026).

References:

Kitiashvili I.N. Investigating the center-to-limb effect using 3D radiative hydrodynamic simulations.
Submitted to ApJ, ArXiv: 2601.03650

Kitiashvili I.N., Kosovichev A.G., Wray A.A., Sadykov V.M., G Guerrero G. 2023.
Leptocline as a shallow substructure of near-surface shear layer in 3D radiative hydrodynamic
simulations. MNRAS, Volume 518, Issue 1, January 2023, Pages 504–512, https://doi.org/10.1093/mnras/stac2946,
arXiv:2203.01484

Wray A.A., Bensassi K., Kitiashvili I.N., Mansour N.N, Kosovichev A.G.
Realistic simulations of Stellar Radiative MHD. In Book: "Variability of the Sun and Sun-like Stars:
from Asteroseismology to Space Weather".  Eds: J.-P. Rozelot, E.S. Babaev, EDP Sciences, 2018. p.39-62.

Wray A.A., Bensassi K., Kitiashvili I. N., Mansour N. N., Kosovichev A. G. 2015.
Simulations of Stellar Magnetoconvection using the Radiative MHD Code StellarBox. ArXiV: 1507.07999.