A collaborative study of plasma irregularities from the HILAT satellite

Convective motion and evolution of high latitude plasma irregularities are described. Data is utilized from the retarding potential analyzer and the ion drift meter on board the HILAT satellite to determine the large scale convective motion of the plasma. To obtain this information it is necessary to recover the satellite attitude data so that corrections for the look angle of the sensor with respect to the satellite can be made. The properties of the satellite attitude variation are described and the procedures for reducing the instrument data to geophysical parameters are outlined. Data from successive overlapping contacts of the satellite from three high latitude stations are utilized to provide coverage of the entire high latitude region. Then derivation of the electrostatic potential distribution is used to describe the global convection pattern. The details of this pattern and its effect on the transport of irregularities from their source region to other locations is studied.