NUMERICAL MODELLING OF ELECTRO-MAGNETOHYDRODYNAMIC DISTURBANCES (E-MHD) IN A TWO-DIMENSIONAL CONFIGURATION IN THE VERTICAL PLANE IN THE IONOSPHERE: SMALL SCALE AND MEDIUM SCALE IONOSPHERIC DISTURBANCES

We have simulated ionospheric disturbances generated by the buoyancy and electrodynamic effects in a two-dimensional configuration in the vertical plane in the ionospheric F region using a simple two-dimensional mathematical model for internal gravity waves propagating in the lower atmosphere, and we have investigated the characteristics (e.g., buyoancy frequency, wavenumber, wavelength, speed) of the ionospheric disturbances. We find that electrohydrodynamic effects are mainly responsible for small scale non-travelling ionospheric disturbances, while magnetohydrodynamic effects are responsible for travelling ionospheric disturbances, including small scale travelling ionospheric disturbances (SSTIDs), medium scale travelling ionospheric disturbances (MSTIDs) and large scale travelling ionospheric disturbances (LSTIDs). Our results are in agreement with the results obtained from observations.