GROUND-BASED OBSERVATIONS OF ION-NEUTRAL COUPLING AT THULE AND QANAQ,GREENLAND

During December 1988, 24 hours of darkness and clear sky conditions pe rmitted continuous observations of the O I (6300 Angstrom) airglow by a Fabry-Perot interferometer located at Thule Air Base, Greenland. Thu s a continuous record of the F region neutral winds was obtained for t hat month. During this same time period, a digital ionosonde located a t Qanaq, Greenland (110 km north of Thule Air Base), was in operation measuring electron density profiles and F region ion drifts. This comb ination of ground-based observations allowed the investigation of ion/ neutral coupling at a temporal resolution of about 15 min. Interplanet ary magnetic field (IMF) data from the IMP 8 satellite were also avail able from December 16 to 24 and indicated intervals of B-z northward I MF conditions during this period. Here we investigate the observed res ponse of the neutral wind to convection changes in the ion drift insid e the polar cap for southward and northward IMF B-z conditions. In par ticular, we establish a control day illustrating the typical antisunwa rd neutral wind and ion drift patterns observed for southward B-z over Thule and Qanaq, and we compare it with observations made when the IM F B-z is directed northward. The observations during periods of northw ard B-z display Sunward directed ion drifts over the polar cap accompa nied by decreasing antisunward directed neutral winds. We investigate these times of northward B-z further and demonstrate that the ion drag term alone cannot describe the observed response in the neutral wind during northward IMF.