Interaction of gravity waves with the ionospheric plasma and the production of electric fields and currents

Abstract

A three-dimensional model of the interaction of the winds of gravity wave origin with the ionospheric plasma has been developed and the electric fields, currents, streaming velocity of electrons relative to ions and the ion convergence rates due to this interaction have been calculated. These calculations show that in the lower E-region, the ion convergence is due to the vertical shears in the E-W wind and the ion convergence rates at the equator are larger than those obtained in the midlatitudes. In the F-region, the ion convergence is due to the shears along the magnetic field in the wind along the magnetic field. Also, the calculations show that this interaction gives rise to large relative velocities between ions and electrons in the direction parallel as well as perpendicular to the magnetic field. The relative velocity between ions and electrons along the magnetic field is found to be sometimes large enough to excite the ion cyclotron instability in some regions. The relative velocity between the ions and electrons in the plane perpendicular to the magnetic field is found to be sufficiently large that when it is added to that due to the electrojet fields, it can partly satisfy the threshold requirements for the excitation of the two-stream plasma instability.