Morphology of large-scale traveling atmospheric disturbances in the polar thermosphere

Using a fully coupled thermosphere-ionosphere-plasmasphere model; we invest igate the morphology of modelled Large-Scale Traveling Atmospheric Disturba nces (LS-TADs, hereinafter TADs) propagating both poleward and equatorward from auroral sources. We confirm observational evidence of daytime ion-drag , reducing equatorward far-field TAD activity. We further suggest an additi onal source-dependent mechanism that associates TADs propagating preferenti ally poleward with an auroral electric field burst that contains an eastwar d rather than a westward component. These poleward TADs are superimposed on the high-speed neutral air winds in the polar cap (originating from the da y-night plasma convection) and exhibit speed and spatial resonance effects with the neutral wind. The direction of propagation is affected by Coriolis forcing due to the Earth's rotation.