Effect of the Anomalous Electron Heating on the Ionospheric Potential in the Global MHD Model.

Conventional approach to the modeling of the ionosphere in global MHD models is to solve a two-dimensional height-integrated electrostatic potential equation driven by the field aligned currents within the magnetosphere. The ionospheric simulation then supplies the inner boundary condition for the MHD solution in the magnetosphere. The ionospheric conductance entering the electrostatic potential equation is usually taken from empirical models including the ionization and deposition of energy due to the auroral precipitation. However, these models do not describe a direct dependence of the ionospheric conductance on the solar wind electric field. An objective of this paper is to modify the ionospheric module of the global LFM model by incorporating the anomalous electron heating which was computed based on realistic models of polar ionosphere. The anomalous electron heating due to the Farley-Buneman instability leads to an increase of plasma density through the reduction of the electron-ion recombination rate. It was shown that the enhancement of the ionospheric conductance due to the anomalous electron heating leads to the drop in the cross polar cap potential making the simulated potential close to realistic values corresponding to strong storms.