Studies of the Dynamics of the High Latitude Ionosphere.

The report surveys theoretical and experimental studies of ionospheric dynamics made during the contract period. Two major aspects of this topic were studied; the outflow of He (+) from the earth's ionosphere, and the effect of magnetospheric convection on the high latitude ionosphere. Model programs were written to study the general characteristics of the outflow of He(+) and also to make quantitative estimates of the escape flux of this ion. An existing model program for studying the effect of convection electric field on the F-region was updated and the N(+) ion was included in the model. Initial work was started to incorporate realistic convection trajectories in the model program. Experimental data from the S3-2 satellite was used to compare with theoretical predictions of both the variation of plasma density with perpendicular electric field and the onset of light ion outflow at high latitudes. While the light ion outflow showed good agreement with theory, the effects of perpendicular electric fields did not and provided further stimulus to incorporate the effect of convection trajectories in our ionospheric models. (Author)