Studies on non-linear Travelling Ionospheric Disturbances and mode coupling within the auroral region

In presence of non-linear perturbations of the thermospheric auroral region produced by travelling ionospheric disturbances (TIDs) during the propagation of atmospheric gravity waves (AGWs), an analytical expression of velocity of the constituent particles is derived through magnetohydrodynamic formalism. Using this, the expressions of Joule heating and viscous heating are derived, whose variations with time have been presented. The height-dependent ratio of the viscous heating rate to the Joule heating rate in generating AGW in the auroral electrojets is determined. Moreover, the mode coupling during transverse wave propagation within the auroral region is being explored, where the expressions of current and field during interactions are derived.