A Quiet-Day Ionospheric Electrodynamics Empirical Model in the Low and Middle Latitudes

In this paper, we develop a climatology model of the ionospheric electric field and potential at low and middle latitudes on quiet time, utilizing plasma drift observed from the ROCSAT-1 satellite. The meridional/vertical and zonal E × B drifts are transformed to the electric fields using modified Apex coordinates under the real geomagnetic field model. The electric field data are adjusted to different solar levels through bilinear fitting, and organized into seasonal, longitudinal, latitudinal bins. The fully normalized associated Legendre functions are chosen as the fitting basis modes. Our model can effectively describe the latitudinal dependence of the electrodynamics parameters cover equatorward of 35° magnetic latitude. The fitted drifts hold the fundamental characteristics of the results observed prior to fitting. The model potential can well shows the typical morphological characteristics that are in great agreement with prior research findings. Furthermore, the potential variations exhibit distinct seasonal, solar flux, and UT dependence under moderate and high solar flux conditions. Within the framework of this model, the potential, electric field, and drift can be mutually converted while maintaining self-consistency.