Last Updated: 11/30/2023


Version: 3.22

SAMI3 (Sami3 is A Model of the Ionosphere) is a seamless, three-dimensional, physics-based model of the ionosphere. It is based on SAMI2, a two-dimensional model of the ionosphere [Huba et al., 2000]. SAMI3 models the plasma and chemical evolution of seven ion species (H+, He+, N+, O+, N+2, NO+ and O+2). The temperature equation is solved for three ion species (H+, He+ and O+) and for the electrons. Ion inertia is included in the ion momentum equation for motion along the geomagnetic field. This is important in modeling the topside ionosphere and plasmasphere where the plasma becomes collisionless. The neutral composition, temperature, and winds can be specified in SAMI3 by the empirical models NRLMSISE00 and HWM14. SAMI3 includes 21 chemical reactions and radiative recombination. SAMI3 uses the EUVAC model for solar radiation. SAMI3 uses a nonorthogonal, nonuniform, fixed grid for the magnetic latitude range +/- 88 degrees. The electric field, driven by the neutral wind dynamo, is determined from the solution of a 2D potential equation [Huba et at., 2008]. The high latitude electric field is calculated from the empirical Weimer model for the potential. The model uses the Richmond apex model [Richmond, 1995] to specify the magnetic field (i.e., IGRF).


SAMI3 3.X sample output diagram


F10.7 (1 day) F10.7A (3 month average) Ap index Kp Index day-of-year year


ion density ion temperature ion velocity electron temperature NmF2 hmF2 TEC (Total Electron Content) Electron Density ExB drifts

Model is time-dependent.


  • Global Ionosphere

Space Weather Impacts

  • Ionosphere variability (navigation, communications)


  • Variablility of Plasma Density
  • Equatorial Anomaly
  • Traveling Ionospheric Disturbances



Code Languages: fortran


Publication Policy

In addition to any model-specific policy, please refer to the General Publication Policy.